physics 2 midterm

]A charge Q accumulates on the hollow metallic dome, of radius R, of a Van de Graaff generator. A probe measures the electric field strength at various points outside the sphere surface. If the probe is initially at a distance 3R from the sphere's center and then is moved to 4R, by what factor will the electric field reading change?

(3/4)²

A point charge of +3.0 µC is located at the origin of a coordinate system and a second point charge of -6.0 µC is at x = 1.0 m. At what point on the x axis is the electrical potential zero?

+0.33 m

Two point charges of values +3.4 and +6.6 µC are separated by 0.10 m. What is the electrical potential at the point midway between the two point charges? (ke = 8.99 x 10^9Nxm^2/C^2)

+0.90 x 10⁶ V

Two point charges of values +3.4 and +6.6 µC, respectively, are separated by 0.20 m. What is the potential energy of this 2-charge system? (ke = 8.99 x 10^9 Nxm^2/C^2)

+1.0 J

We have a hollow metallic sphere with charge -5.0 µC and radius 5.0 cm. We insert a +10-µC charge at the center of the sphere through a hole in the surface. What charge now rests on the outer surface of the sphere?

+5 µC

Four charges are at the corners of a square, with B and C on opposite corners. Charges A and D, on the other two corners, have equal charge, while both B and C have a charge of +1.0 C. What is the charge on A so that the force on B is zero?

-0.35 C

Q1 has 50 electric field lines radiating outward and Q2 has 100 field lines converging inward. What is the ratio Q1/Q2?

-1/2

An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of +10 µC carefully placed at the center of the sphere through a hole in the latter's surface. What charge resides inner surface of the sphere?

-10µC

In the circuit segment shown if I = 7 mA and Q = 50 µC, what is the potential difference, VA - VB?

-20 V

Two point charges are placed along a horizontal axis with the following values and positions: +3.0 µC at x = 0 cm and -7.0 µC at x = 20 cm. At what point along the x axis is the electric field zero?

-38

A point charge of +3.0 µC is located at the origin of a coordinate system and a second point charge of -6.0 µC is at x = 1.00 m. What is the electric potential at the x = 0.50 m point? (ke= 8.99 x 10^9 Nxm^2/C^2)

-5.4 x 10 ⁴ V

A charge of +2 C is at the origin. When charge Q is placed at 2 m along the positive x axis, the electric field at 2 m along the negative xaxis becomes zero. What is the value of Q?

-8C

Two equal charges, each Q, are separated by some distance. What third charge would need to be placed half way between the two charges so that the net force on each charge would be zero?

-Q/4

A thin uncharged conducting spherical shell has a charge q carefully placed at its center through a small hole in the shell. The charge q does not touch the shell. What is the charge on the shell?

0

A certain material is in a room at 27°C. If the absolute temperature (K) of the material is tripled, its resistance doubles. (Water freezes at 273 K.) What is the value for α, the temperature coefficient of resistivity?

0.0017 (°C)⁻¹

A 0.25-µF capacitor is connected to a 400-V battery. What potential energy is stored in the capacitor?

0.020 J

A circular loop carrying a current of 1.0 A is oriented in a magnetic field of 0.35 T. The loop has an area of 0.24 m^2 and is mounted on an axis, perpendicular to the magnetic field, which allows the loop to rotate. What is the torque on the loop when its plane is oriented at a 25° angle to the field?

0.076 Nm

A circular loop carrying a current of 1.0 A is oriented in a magnetic field of 0.35 T. The loop has an area of 0.24 m2 and is mounted on an axis, perpendicular to the magnetic field, which allows the loop to rotate. If the plane of the loop is oriented parallel to the field, what torque is created by the interaction of the loop current and the field?

0.084 Nm

A proton initially moves left to right long the x axis at a speed of 2.00 x 10^3 m/s. It moves into an electric field, which points in the negative x direction, and travels a distance of 0.200 m before coming to rest. If the proton's mass and charge are 1.67 x 10^-27 kg and 1.60 x 10^-19 C respectively, what is the magnitude of the electric field?

0.104 N/C

A 1 000-V battery, a 3 000-Ω resistor and a 0.50-µF capacitor are connected in series with a switch. The time constant for such a circuit, designated by the Greek letter, , is defined as the time that the capacitor takes to charge to 63% of its capacity after the switch is closed. What is the current in the circuit at a time interval of seconds after the switch has been closed?

0.12 A

The resistance of a platinum wire is to be calibrated for low-temperature work. A platinum wire with resistance 1.000 Ω at 20°C is immersed in liquid nitrogen at 77 K (-196°C). If the temperature response of the platinum wire is linear, what is the expected resistance of the platinum wire at -196°C? αplatinum = 3.92 x 10^-3 (°C)^-1

0.153 Ω

A 9.0-V battery moves 20 mC of charge through a circuit running from its positive terminal to its negative terminal. How much energy was delivered to the circuit?

0.18 J

If ε = 9.0 V, what is the current in the 15-Ω resistor?

0.20 A

A proton (+1.6 x 10^-19 C) moves 10 cm along the direction of an electric field of strength 3.0 N/C. The electrical potential difference between the proton's initial and ending points is:

0.30 V

A 1 000-V battery, a 3 000-Ω resistor and a 0.50-µF capacitor are connected in series with a switch. The capacitor is initially uncharged. What is the value of the current the moment after the switch is closed?

0.33 A

Very large capacitors have been considered as a means for storing electrical energy. If we constructed a very large parallel-plate capacitor of plate area 1.0 m2 using paper (κ = 3.7) of thickness 1.0 mm as a dielectric, how much electrical energy would it store at a plate voltage of 5 000 V? (ε₀ = 8.85 x 10^-12 C^2/Nxm^2)

0.41 J

A series RC circuit has a time constant of 1.0 s. The battery has a voltage of 50 V and the maximum current just after closing the switch is 500 mA. The capacitor is initially uncharged. What is the charge on the capacitor 2.0 s after the switch is closed?

0.43 C

Three capacitors of 1.0, 1.5, and 2.0 µF are connected in series. Find the combined capacitance.

0.46 µF

A resistor is connected to a battery with negligible internal resistance. If you replace the resistor with one that has twice the resistance, by what factor does the power dissipated in the circuit change?

0.50

A 60-W light bulb is in a socket supplied with 120 V. What is the current in the bulb?

0.50 A

A circular coil (radius = 0.40 m) has 160 turns and is in a uniform magnetic field. If the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is 0.16 Nm when the current in the coil is 4.0 mA. What is the magnitude of the magnetic field?

0.50 T

A light bulb has resistance of 240 Ω when operating at 120 V. Find the current in the light bulb.

0.50 a

Three resistors connected in parallel have individual values of 4.0, 6.0 and 10.0 Ω, respectively. If this combination is connected in series with a 12-V battery and a 2.0-Ω resistor, what is the current in the 10-Ω resistor?

0.59 A

A current-carrying wire of length 50 cm is positioned perpendicular to a uniform magnetic field. If the current is 10.0 A and it is determined that there is a resultant force of 3.0 N on the wire due to the interaction of the current and field, what is the magnetic field strength?

0.60 T

The dielectric strength of Rutile is 6.0 x 10^6 V/m, which corresponds to the maximum electric field that the dielectric can sustain before breakdown. What is the maximum charge that a 10^-10-F capacitor with a 1.0-mm thickness of Rutile can hold?

0.60 µC

What is the equivalent capacitance between points a and b? All capacitors are 1.0 µF.

0.60 µF

How much current is flowing in one of the 10-Ω resistors?

0.8 A

A copper cable needs to carry a current of 200 A with a power loss of only 3.0 W/m. What is the required radius of the copper cable? (The resistivity of copper is 1.7 X 10^-8 Ωm.)

0.85 cm

When a 24.0-Ω resistor is connected across a 12.0-V battery, a current of 482 mA flows. What is the internal resistance of the battery?

0.9 Ω

If a lamp has a resistance of 120 Ω when it operates at 100 W, what current does it carry?

0.91 A

If C1 = 25 µF, C2 = 20 µF, C3 = 10 µF, and ∆V0 = 21 V, determine the energy stored by C2.

0.91 mJ

A nichrome wire has a radius of 0.50 mm and a resistivity of 1.5 X 10^-6 Ωm. If the wire carries a current of 0.50 A, what is the potential difference per unit length along this wire?

0.95 V/m

Two singly ionized isotopes, X and Y, of the same element move with the same speed perpendicular to a uniform magnetic field. Isotope X follows a path of radius 3.35 cm while isotope Y moves along a path 3.43 cm in radius. What is the ratio of the two isotope masses, mX/mY?

0.977

A proton and a deuteron are moving with equal velocities perpendicular to a uniform magnetic field. A deuteron has the same charge as the proton but has twice its mass. The ratio of the magnetic force on the proton to that on the deuteron is:

1

An electron in a TV picture tube is accelerated through a potential difference of 10 kV before it hits the screen. What is the kinetic energy of the electron in electron volts? (1 eV = 1.6 X 10^-19 J)

1.0 X 10 ⁻⁴ eV

A 0.25-µF capacitor is connected to a 400-V battery. Find the charge on the capacitor.

1.0 x 10⁻⁴

Two long parallel wires 40 cm apart are carrying currents of 10 A and 20 A in the same direction. What is the magnitude of the magnetic field halfway between the wires?

1.0 x 10⁻⁵ T

A proton initially moves left to right long the x axis at a speed of 2.00 x 10^3 m/s. It moves into an electric field, which points in the negative x direction, and travels a distance of 0.200 m before coming to rest. What acceleration magnitude does the proton experience?

1.00 x 10⁷ m/s²

In x-ray machines, electrons are subjected to electric fields as great as 6.0 x 10^5 N/C. Find an electron's acceleration in this field. (me = 9.11 x 10^-31 kg, e = 1.6 x 10^-19 C)

1.1 x 10¹⁷ m/s²

Three resistors, with values of 2.0, 4.0 and 8.0 Ω, respectively, are connected in parallel. What is the overall resistance of this combination?

1.1 Ω

Two protons, each of charge 1.60 x 10^-19 C, are 2.00 x 10^-5 m apart. What is the change in potential energy if they are brought 1.00 x 10^-5 m closer together? (ke = 8.99 x 10^9N·m^2/C^2)

1.15 x 10⁻²³

A steam turbine at an electric power plant delivers 4 500 kW of power to an electrical generator which converts 95% of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers at 3 600 V?

1.2 x 10³ A

A ping-pong ball covered with a conducting graphite coating has a mass of 5.0 x 10^-3 kg and a charge of 4.0 µC. What electric field directed upward will exactly balance the weight of the ball? (g = 9.8 m/s^2)

1.2 x 10⁴ N/C

Number 10 copper wire (radius = 1.3 mm) is commonly used for electrical installations in homes. What is the voltage drop in 40 m of #10 copper wire if it carries a current of 10 A? (The resistivity of copper is 1.7 x 10^-8 Ωm.)

1.3 V

An electron is released from rest at the negative plate of a parallel-plate capacitor. If the distance across the plate is 5.0 mm and the potential difference across the plate is 5.0 V, with what velocity does the electron hit the positive plate? (me = 9.1 x 10^-31 kg, e = 1.6 x 10^-19 C)

1.3 x 10⁶ m/s

A Van de Graaff generator has a spherical dome of radius 20 cm. Operating in dry air, where "atmospheric breakdown" is at Emax = 3.0 x10^6 N/C, what is the maximum charge that can be held on the dome? (ke = 8.99 x 10^9 Nxm^2/C^2)

1.3 x 10⁻⁵ C

Charge A and charge B are 3.00 m apart, and charge A is +2.00 C and charge B is +3.00 C. Charge C is located between them at a certain point and the force on charge C is zero. How far from charge A is charge C?

1.35 m

By what factor is the resistance of a copper wire changed when its temperature is increased from 20°C to 120°C? The temperature coefficient of resistivity for copper = 3.9 x 10^-3 (°C)^-1.

1.39

A proton moving at a speed of 3.8 x 106 m/s cuts across the lines of a magnetic field at an angle of 70°. The strength of the field is 0.25 x 10^-4 T. What is the magnitude of the force acting on the proton? (qp = 1.6 x 10^-19 C)

1.4 x 10⁻¹⁷ N

A circuit contains a 6.0-V battery, a 4.0-Ω resistor, a 0.60-µF capacitor, an ammeter, and a switch all in series. What will be the current reading immediately after the switch is closed?

1.5 A

What is the current through the 8-Ω resistor?

1.5 A

A 500-W heater carries a current of 4.0 A. How much does it cost to operate the heater for 30 min if electrical energy costs 6.0 cents per kWh?

1.5 cents

A 1 000-V battery, a 3 000-Ω resistor and a 0.50-µF capacitor are connected in series with a switch. The time constant for such a circuit, designated by the Greek letter, , is defined as the time required to charge the capacitor to 63% of its capacity after the switch is closed. What is the value of for this circuit?

1.5 x 10⁻³ s

If ε = 20 V, at what rate is thermal energy being generated in the 20-Ω resistor?

1.6 W

A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 x 10^-4 T. What is the size of the force on the wire?

1.6 x 10⁻⁴ N

A 100-m-long wire carrying a current of 4.0 A will be accompanied by a magnetic field of what strength at a distance of 0.050 m from the wire? (magnetic permeability in empty space µ0 = 4π x10^-7 Tm/A)

1.6 x 10⁻⁵ T

At what distance from a point charge of 8.0 µC would the electrical potential be 4.2 x 10^4V? (ke = 8.99 x 10^9 Nxm^2/C^2)

1.7 m

A solid conducting sphere of 10 cm radius has a net charge of 20 nC. If the potential at infinity is taken as zero, what is the potential at the center of the sphere?

1.8 x 10³ V

Two capacitors with capacitances of 1.5 µF and 0.25 µF, respectively, are connected in parallel. The system is connected to a 50-V battery. What electrical potential energy is stored in the 1.5-µF capacitor?

1.9 x 10⁻³ J

A uniform electric field, with a magnitude of 600 N/C, is directed parallel to the positive x-axis. If the potential at x = 3.0 m is 1 000 V, what is the change in potential energy of a proton as it moves from x = 3.0 m to x = 1.0 m? (qp = 1.6 x 10^-19 C)

1.9 x 10⁻¹⁶ J

A nichrome wire has a radius of 0.50 mm and a resistivity of 1.5 X 10^-6 Ωm. What is the resistance per unit length of this wire?

1.9 Ω/m

A pair of parallel plates, forming a capacitor, are connected to a battery. While the capacitor is still connected to the battery maintaining a constant voltage, the plates are pulled apart to double their original distance. What is the ratio of the final energy stored to the original energy stored?

1/2

If the distance between two negative point charges is increased by a factor of three, the resultant potential energy is what factor times the initial potential energy?

1/3

Four identical 1 mF capacitors are connected together electrically. What is the least possible capacitance of the combination?

1/4 mF

If the distance between two point charges is tripled, the mutual force between them will be changed by what factor?

1/9

Replacing a wire resistor with another of the same material and length but with three times the diameter will have the effect of changing the resistance by what factor?

1/9

What is the equivalent capacitance of the combination shown?

10 µF

Resistors of values 6.0Ω, 4.0Ω, 10.0Ω and 7.0Ω are combined as shown. What is the equivalent resistance for this combination?

10.7 Ω

A high-voltage transmission line carries 1 000 A at 700 kV for a distance of 100 miles. If the resistance in the wire is 1 Ω/mile, what is the power loss due to resistive losses?

100 MW

About how many electrons are in 30 grams of water (H2O)?

10²⁵

Different units can be used to measure the same physical quantity, differing only by some multiplicative factor. The cgs unit for magnetic field, the gauss, is equal to ____ tesla.

10⁻⁴

An electric toaster requires 1 100 W at 110 V. What is the resistance of the heating coil?

11.0 Ω

When a 24.0-Ω resistor is connected across a 12.0-V battery, a current of 482 mA flows. What is the resulting terminal voltage of the battery?

11.6 V

If a lamp has resistance of 120 Ω when it operates at 100 W, what is the applied voltage?

110 V

If three 4.0-µF capacitors are connected in parallel, what is the combined capacitance?

12 µF

A solar panel measures 80 cm x 50 cm. In direct sunlight, the panel delivers 3.2 A at 15 V. If the intensity of sunlight is 1 000 W/m2, what is the efficiency of the solar panel in converting solar energy into electrical energy?

12%

Superconductors can carry very large currents with no resistance. If a superconducting wire is formed into a solenoid of length 50.0 cm with 500 turns, what is the magnetic field inside the solenoid when the current is 10^4 A? (µ0 = 4π x 10^-7 Tm/A)

12.6 T

When charges qa, qb, and qc are placed respectively at the corners a, b, and c of a right triangle, the potential at the midpoint of the hypotenuse is 20 V. When the charge qa is removed, the potential at the midpoint becomes 15 V. When, instead, the charge qb is removed (qa and qc both in place), the potential at the midpoint becomes 12 V. What is the potential at the midpoint if only the charge qc is removed from the array of charges?

13 V

If ε = 24 V, at what rate is thermal energy generated in the 20-Ω resistor?

13 w

Suppose that a voltage surge produces 140 V for a moment in a 120-V line. What will temporarily be the output of a 100-W light bulb assuming its resistance does not change?

136 W

Three resistors, with values of 2.0, 4.0 and 8.0 Ω, respectively, are connected in series. What is the overall resistance of this combination?

14.0 Ω

A tungsten wire is used to determine the melting point of indium. The resistance of the tungsten wire is 3.000 Ω at 20°C and increases to 4.850 Ω as the indium starts to melt. αtungsten = 4.50 x 10^-3 (°C)^-1. What is the melting temperature of indium?

157° C

In a circuit, a current of 2.0 A is drawn from a battery. The current then divides and passes through two resistors in parallel. One of the resistors has a value of 64 Ω and the current through it is 0.40 A. What is the value of the other resistor?

16 Ω

A "sandwich" is constructed of two flat pieces of metal (2.00 cm on a side) with a 2.00-mm-thick piece of a dielectric called Rutile (κ = 100) in between them. What is the capacitance? (ε₀ = 8.85 x 10^-12 C^2/Nxm^2)

177 pF

A capacitor is made by taking two sheets of aluminum foil, each 0.022 mm thick and placing between them a sheet of paper which comes from a ream of 500 sheets, the ream being 5.5 cm thick with sheets measuring 216 mm by 279 mm (the usual 8 1/2 by 11). What is the capacitance of the capacitor made this way if the dielectric constant of the paper is 3.7? (ε₀= 8.85 x 10^-12 C^2/Nxm^2)

18 nF

A voltage source of 10 V is connected to a series RC circuit where R = 2.0 X 10^6 Ω, and C = 3.0 µF. Find the amount of time required for the current in the circuit to decay to 5% of its original value. Hint: This is the same amount of time for the capacitor to reach 95% of its maximum charge.

18 s

A metallic conductor has a resistivity of 18 x 10^-6 Ωm. What is the resistance of a piece that is 30 m long and has a uniform cross sectional area of 3.0 x 10^-6 m^2?

180Ω

A pair of parallel plates, forming a capacitor, are charged. The plates are pulled apart to double the original separation, the charges on the plates remaining the same. What is the ratio of the final energy stored to the original energy stored?

2

Two parallel-plate capacitors have the same plate area, and the gap between the plates is filled with a dielectric with a dielectric constant equal to 4. The gap in capacitor A is one half that in Capacitor B. What is the ratio of the capacitance of A to B?

2

Electrons in a particle beam each have a kinetic energy of 3.2 x 10^-17 J. What is the magnitude of the electric field that will stop these electrons in a distance of 0.1 m? (e = 1.6 x 10^-19 C)

2 000 N/C

If a 500-W heater carries a current of 4.00 A, what is the voltage across the ends of the heating element?

2 000 V

A uniform electric field, with a magnitude of 600 N/C, is directed parallel to the positive x-axis. If the potential at x = 3.0 m is 1 000 V, what is the potential at x = 1.0 m?

2 200 V

An electron moves through a region of crossed electric and magnetic fields. The electric field E = 2 000 V/m and is directed straight down. The magnetic field B = 0.80 T and is directed to the left. For what velocity v of the electron into the paper will the electric force exactly cancel the magnetic force?

2 500 m/s

A wire carries a steady current of 0.1 A over a period of 20 s. What total charge passes through the wire in this time interval?

2 C

A superconducting wire carries a current of 10^4 A. Find the magnetic field at a distance of 1.0 m from the wire. (µ0 = 4π x 10^-7 Tm/A)

2 x 10⁻³ T

A copper wire of length 25 cm is in a magnetic field of 0.20 T. If it has a mass of 10 g, what is the minimum current through the wire that would cause a magnetic force equal to its weight?

2.0 A

Two resistors of values 6.0 and 12.0 Ω are connected in parallel. This combination in turn is hooked in series with a 4.0-Ω resistor and a 24-V battery. What is the current in the 6-Ω resistor?

2.0 A

A 10.0-µF capacitor is attached to a 20-V power supply. How much energy is stored in the capacitor?

2.0 x 10⁻³ J

An electron is moving at a speed of 6.0 x 10^6 m/s at an angle of 30° with respect to a uniform magnetic field of 8.0 x 10^-4 T. What is the radius of the resulting helical path? (me = 9.11 x 10^-31 kg, qe = 1.6 x 10^-19 C)

2.1 cm

If an electron is accelerated from rest through a potential difference of 1 200 V, find its approximate velocity at the end of this process. (e = 1.6 x 10^-19 C; me = 9.1 x 10^-31 kg)

2.1 x 10 ⁷ m/s

Four 1.5-volt AA batteries in series power a transistor radio. If the batteries hold a total charge of 240 C, how long will they last if the radio has a resistance of 200 Ω?

2.2 h

The current in an electron beam in a cathode-ray tube is measured to be 70 µA. How many electrons hit the screen in 5.0 s? (e = 1.6 x10^-19 C)

2.2 x 10¹⁵ electrons

What is the equivalent resistance for these 3.00-Ω resistors?

2.25 Ω

A 9.0-V battery is connected between two parallel metal plates 4.0 mm apart. What is the magnitude of the electric field between the plates?

2.3 x 10³ N/C

An electron with a speed of 2.0 x 10^6 m/s moves into a uniform electric field of 500 N/C that is parallel to the electron's motion. How long does it take to bring the electron to rest? (me = 9.11 x 10^-31 kg, e = 1.6 x 10^-19 C)

2.3 x 10⁻⁸ s

A metallic object holds a charge of -3.8 x 10⁻⁶ C. What total number of electrons does this represent? (e = 1.6 x 10⁻¹⁹ C is the magnitude of the electronic charge.)

2.4 x 10¹³

How much charge can be placed on a capacitor of plate area 10 cm2 with air between the plates before it reaches "atmospheric breakdown" where E = 3.0 x 10^6 V/m? (ε0 = 8.85 x 10^-12 C^2/Nxm^2)

2.7 x 10⁻⁸ C

Three 8.0-Ω resistors are connected in parallel. What is their equivalent resistance?

2.7 Ω

If a metallic wire of cross sectional area 3.0 x 10^-6 m^2 carries a current of 6.0 A and has a mobile charge density of 4.24 x 10^28 carriers/m^3, what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 x 10^-19 C)

2.9 x 10⁻⁴ m/s

An electron is sent at high speed toward a gold nucleus (charge +79e). What is the electrical force acting on the electron when it is 3.0 x10^-14 m away from the gold nucleus? (e = 1.6 x 10^-19 C, ke = 8.99 x 109 N·m^2/C^2)

20 N

Two point charges, separated by 1.5 cm, have charge values of +2.0 and -4.0 µC, respectively. Suppose we determine that 10 field lines radiate out from the +2.0-µC charge. If so, what might be inferred about the -4.0-µC charge with respect to field lines?

20 radiate in

A high-voltage power line 20 m above the ground carries a current of 2 000 A. What is the magnetic field due to the current directly underneath the power line? (µ0 = 4π x 10^-7 Tm/A)

20 µT

A hair dryer draws 1 200 W, a curling iron draws 800 W, and an electric light fixture draws 500 W. If all three of these appliances are operating in parallel on a 120-V circuit, what is the total current drawn?

20.8 A

Carbon has a negative temperature coefficient of resistance of -0.5 x 10^-3 (°C)^-1. What temperature increase would result in a resistance decrease of 1% for a carbon resistor?

20°C

The following three appliances are connected to a 120-V house circuit: i) toaster, 1 200 W, ii) coffee pot, 750 W, and iii) microwave, 800 W. If all were operated at the same time, what total current would they draw?

23 A

If C = 36 µF, determine the equivalent capacitance for the combination shown.

24 µF

What is the equivalent capacitance of the combination shown?

24 µF

A solenoid with 500 turns, 0.10 m long, carrying a current of 4.0 A and with a radius of 10^-2 m will have what strength magnetic field at its center? (magnetic permeability in empty space µ0 = 4π x 10^-7 Tm/A)

250 x 10⁻⁴ T

A 20-Ω platinum wire at 20°C with a temperature coefficient of resistivity of 3.9 x 10^-3 (°C)^-1 will have what resistance at 100°C?

26 Ω

The two ends of a 3.0-Ω resistor are connected to a 9.0-V battery. What is the total power delivered by the battery to the circuit?

27 w

Two cylindrical resistors are made of the same material and have the same resistance. The resistors, R1 and R2, have different radii, r1and r2, and different lengths, L1 and L2. Which of the following relative values for radii and lengths would result in equal resistances?

2r₁ = r₂ and 4L₁=L₂

A superconducting solenoid is to be designed to generate a magnetic field of 5.00 T. If the solenoid winding has 1 000 turns/m, what is the required current? (µ0 = 4π x 10^-7 Tm/A)

3 980 A

At the Fermilab accelerator in Weston, Illinois, singly-charged ions with momentum 4.8 x 10^-16 kgm/s are held in a circular orbit of radius 1 km by an upward magnetic field. What B-field must be used to maintain the ions in this orbit? (qion = 1.6 x 10^-19 C)

3 T

The two ends of a 3.0-Ω resistor are connected to a 9.0-V battery. What is the current through the resistor?

3.0 A

Three 4.0-Ω resistors are connected in parallel to a 12.0-V battery. What is the current in any one of the resistors?

3.0 A

Two parallel wires are separated by 0.25 m. Wire A carries 5.0 A and Wire B carries 10 A, both currents in the same direction. The force on 0.80 m of Wire A is:

3.2 X 10⁻⁵ N

A flashlight bulb operating at a voltage of 4.5 V has a resistance of 8.0 Ω. How many electrons pass through the bulb filament per second (e = 1.6 x 10^-19 C)?

3.5 x 10¹⁸

An 8.00-Ω resistor is dissipating 100 watts. What are the current through it, and the difference of potential across it?

3.54 A, 28.3 V

Find the electrical potential at 0.15 m from a point charge of 6.0 µC. (ke = 8.99 x 10^9 Nxm^2/C^2)

3.6 x 10⁵ V

In a thundercloud there may be an electric charge of +40 C near the top of the cloud and -40 C near the bottom of the cloud. These charges are separated by about 2.0 km. What is the electric force between these two sets of charges? (ke = 8.99 x 10^9 N·m^2/C^2)

3.6 x 10⁶ N

A circuit contains a 6.0-V battery, a 4.0-Ω resistor, a 0.60-µF capacitor, an ammeter, and a switch in series. What will be the charge on the capacitor 10 min after the switch is closed?

3.6 µC

A proton is released such that it has an initial speed of 4.0 x 10^5 m/s from left to right across the page. A magnetic field of 1.2 T is present at an angle of 30° to the horizontal direction (or positive x axis). What is the magnitude of the force experienced by the proton? (qp = 1.6 x 10^-19 C)

3.8 x 10⁻¹⁴ N

If a 500-W heater carries a current of 4.00 A, what is the resistance of the heating element?

31.3 Ω

Two capacitors with capacitances of 1.0 and 0.50 µF, respectively, are connected in series. The system is connected to a 100-V battery. What charge accumulates on the 1.0-µF capacitor?

33 µC

An electric clothes dryer draws 15 A at 220 V. If the clothes put into the dryer have a mass of 7.0 kg when wet and 4.0 kg dry, how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water, Lv = 2.26 x 10^6 J/kg.)

34 min

The electric field in a cathode ray tube is supposed to accelerate electrons from 0 to 1.60 x 10^7 m/s in a distance of 2.00 cm. What electric field is required? (me = 9.11 x 10^-31 kg and e = 1.60 x 10^-19 C)

36 400 N/C

A parallel-plate capacitor has a capacitance of 20 µF. What potential difference across the plates is required to store 7.2 x 10^-4 C on this capacitor?

36 V

Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the resulting mutual force between them change?

4

What is the current flowing through the 2-Ω resistor?

4 A

A closed surface contains the following point charges: 6 C, 4 C, -2 C, -4 C. The electric flux coming out of the surface is:

4 C/ε₀

Two identical iron spheres have equal positive charges and the force between them when they are 1 m apart is 1 N. What percentage of the electrons has been removed from each sphere if each sphere has 1 mole (6 x 10^23) of iron atoms? (ke = 8.99 x 10^9 Nxm^2/C^2, the atomic number of iron is 26, and the electron charge is -1.6 x 10^-19 C)

4 x 10⁻¹⁰%

Two resistors of values 6.0 and 12.0 Ω are connected in parallel. This combination in turn is hooked in series with a 2.0-Ω resistor and a 24-V battery. What is the current in the 2-Ω resistor?

4.0 A

A spherical volume of space has an electric field of intensity 100 N/C directed radially outward from its surface of radius 0.600 m. What is the net charge enclosed within this surface?

4.0 nC

Two electrons are separated by one cm. What is the ratio of the electric force to the gravitational force between them? (me = 9.11 x 10⁻³¹ kg, ke = 8.99 x 10⁹ Nxm²/C², G = 6.67 x 10⁻¹¹ Nxm²/kg², and e = 1.6 x 10⁻¹⁹ C)

4.2x 10⁴²

An electron with velocity v = 1.0 x 10^6 m/s is sent between the plates of a capacitor where the electric field is E = 500 V/m. If the distance the electron travels through the field is 1.0 cm, how far is it deviated (Y) in its path when it emerges from the electric field? (me = 9.1 x10^-31 kg, e = 1.6 x 10^-19 C)

4.4 mm

Four point charges are on the rim of a circle of radius 10 cm. The charges are (in µC) +0.50, +1.5, -1.0, -0.50. If the electrical potential at the circle's center due to the +0.5 charge alone is 4.5 x 10^4 V, what is the total potential at the center due to the four charges combined?

4.5 x 10⁴ V

Charges of 4.0 µC and -6.0 µC are placed at two corners of an equilateral triangle with sides of 0.10 m. At the third corner, what is the electric field magnitude created by these two charges? (ke = 8.99 x 10^9 N·m^2/C^2)

4.8 x 10⁶ N/C

A proton (+1.6 x 10^-19 C) moves 10 cm on a path in the direction of a uniform electric field of strength 3.0 N/C. How much work is done on the proton by the electrical field?

4.8 x 10⁻²

A proton (+1.6 x 10^-19 C) moves 10 cm on a path in the direction of a uniform electric field of strength 3.0 N/C. How much work is done on the proton by the electrical field?

4.8 x 10⁻²⁰ J

A charge Q accumulates on the hollow metallic dome, of radius R, of a Van de Graaff generator. A probe measures the electric field strength at various points outside the sphere surface. By what factor will the electric field value at the 2R distance be changed if the charge value were increased to (4/3)Q?

4/3

If a doubly-ionized oxygen atom (O-2) is accelerated from rest by going through a potential difference of 20 V, what will be the change in its kinetic energy?

40 eV

A 10-V-emf battery is connected in series with the following: a 2-µF capacitor, a 2-Ω resistor, an ammeter, and a switch, initially open; a voltmeter is connected in parallel across the capacitor. At the instant the switch is closed, what are the current and capacitor voltage readings, respectively?

5 A, zero V

A metal wire has a resistance of 25.00 Ω under room temperature conditions of 25°C. When the wire is heated to 85C the resistance increases by 0.75 Ω. What is the temperature coefficient of resistivity of this metal?

5.0 x 10⁻⁴ (°C)⁻¹

A 0.20-m-long metal rod has a radius of 1.0 cm and a resistance of 3.2 x10^-5 Ω. What is the resistivity of the metal?

5.0 x 10⁻⁸ Ωm

You measure a 25.0-V potential difference across a 5.00-Ω resistor. What is the current flowing through it?

5.00 A

The average distance of the electron from the proton in the hydrogen atom is 0.51 x 10^-10 m. What is the electric field from the proton's charge at the location of the electron? (ke = 8.99 x 10^9 Nxm^2/C^2, e = 1.6 x 10^-19 C)

5.5 x 10¹¹ N/C

Two capacitors with capacitances of 1.0 µF and 0.50 µF, respectively, are connected in series. The system is connected to a 100-V battery. What electrical potential energy is stored in the 1.0-µF capacitor?

5.6 x 10⁻⁴ J

When a 24.0-Ω resistor is connected across a 12.0-V battery, a current of 482 mA flows. What is the power output delivered by the emf of the battery?

5.78 W

If C = 10 µF, what is the equivalent capacitance for the combination shown?

5.8 µF

Using a 1-mF capacitor, a 2-mF capacitor, and a 3-mF capacitor, which of the following capacitances cannot be made by a combination that uses all three? (Hint: At most only 2 combinations must be considered to determine the correct answer.)

5/11 mF

Electrons in an x-ray machine are accelerated from rest through a potential difference of 50 000 V. What is the kinetic energy of each of these electrons in eV?

50 keV

An electric car is designed to run off a bank of 12-V batteries with total energy storage of 3.0 x 10^7 J. If the electric motor draws 6 000 W in moving the car at a steady speed of 10 m/s, how far will the car go before it is "out of juice?"

50 km

An electric car is designed to run off a bank of 12-V batteries with total energy storage of 3.0 x 10^7 J. If the electric motor draws 6 000 W, what current will be delivered to the motor?

500 A

Consider the circuit shown in the figure. What power is dissipated by the entire circuit?

52 W

What is the maximum number of 60-W light bulbs you can connect in parallel in a 120-V home circuit without tripping the 30-A circuit breaker?

59

A series RC circuit, which is made from a battery, a switch, a resistor, and a 3.0-µF capacitor, has a time constant of 9.0 ms. If an additional 6.0-µF is added in series to the 3.0-µF capacitor, what is the resulting time constant?

6.0 ms

Some superconductors are capable of carrying a very large quantity of current. If the measured current is 1.00 x 10^5 A, how many electrons are moving through the superconductor per second? (e = 1.60 x 10^-19 C)

6.25 x 10²³

How much power is being dissipated by one of the 10-Ω resistors?

6.4 W

An electron with a charge value of 1.6 x 10^-19 C is moving in the presence of an electric field of 400 N/C. What force does the electron experience?

6.4 x 10⁻¹⁷ N

The heating coil of a hot water heater has a resistance of 20 Ω and operates at 210 V. How long a time is required to raise the temperature of 200 kg of water from 15°C to 80°C? (The specific heat for water = 10^3 cal/kg°C and 1.0 cal = 4.186 J.)

6.9 h

An incredible amount of electrical energy passes down the funnel of a large tornado every second. Measurements taken in Oklahoma at a distance of 9.00 km from a large tornado showed an almost constant magnetic field of 1.50 x 10^-8 T associated with the tornado. What was the average current going down the funnel? (µ0 = 4π x 10^-7 Tm/A)

675 A

How long is a wire made from 100 cm^3 of copper if its resistance is 8.5 ohms? The resistivity of copper is 1.7 x 10-5 Ω·m.

7.1 m

A proton moving at 3.0 x 104 m/s is projected at an angle of 30° above a horizontal plane. If an electric field of 400 N/C is acting down, how long does it take the proton to return to the horizontal plane? (Hint: Ignore gravity. mproton = 1.67 x 10^-27 kg, qproton = 1.6 x 10^-19C)

7.8 x 10⁻⁷ s

A high-voltage transmission line carries 1 000 A at 700 000 V. What is the power carried by the line?

700 MW

Two capacitors with capacitances of 1.5 and 0.25 µF, respectively, are connected in parallel. The system is connected to a 50-V battery. What charge accumulates on the 1.5-µF capacitor?

75 µC

In a certain material there is a current of 16 A flowing through a surface to the right, and there is an equal amount of positive and negative charge passing through the surface producing the current. How much negative charge passes through the surface?

8 C/s toward the left

When charges qa, qb, and qc are placed respectively at the corners a, b, and c of a right triangle, the potential at the midpoint of the hypotenuse is 20 V. When the charge qa is removed, the potential at the midpoint becomes 15 V. When, instead, the charge qb is removed (qa and qc both in place), the potential at the midpoint becomes 12 V. What is the potential at the midpoint if both charges qa and qc are removed?

8 V

A high voltage transmission line of diameter 2 cm and length 200 km carries a steady current of 1 000 A. If the conductor is copper with a free charge density of 8 x 10^28 electrons/m3, how long does it take one electron to travel the full length of the cable? (e = 1.6 x10^-19 C)

8 x 10⁸ s

If I1 goes to the right through R1, I2 goes to the right through R2, and I3 goes to the right through R3, what is the resulting equation resulting from applying Kirchhoff's loop rule for a clockwise loop around the perimeter of the circuit?

8.0 V- I₁R₁ + I₃R₃ =0

An electron in a cathode ray tube is accelerated through a potential difference of 5.0 kV. What kinetic energy does the electron gain in the process? (e = 1.6 x 10^-19 C)

8.0 x 10⁻¹⁶ J

Two resistors of values 6.0 and 12.0 Ω are connected in parallel. This combination in turn is hooked in series with a 4.0-Ω resistor. What is the overall resistance of this combination?

8.0 Ω

A rectangular coil (0.20 m 0.80 m) has 200 turns and is in a uniform magnetic field of 0.30 T. If the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is 0.080 Nm. What is the current in the coil?

8.3 mA

A proton, mass 1.67 x 10^-27 kg and charge +1.6 x 10^-19 C, moves in a circular orbit perpendicular to a uniform magnetic field of 0.75 T. Find the time for the proton to make one complete circular orbit.

8.7 x 10⁻⁸ s

In Millikan's oil drop experiment, if the electric field between the plates was of just the right magnitude, it would exactly balance the weight of the drop. Suppose a tiny spherical oil droplet of radius 1.6 x 10⁴ cm carries a charge equivalent to one electron. What electric field is required to balance the weight? (The density of oil is 0.85 g/cm³, e = 1.6 x 10⁻¹⁹ C.)

8.9 x 10⁵ N/C

A water pump draws about 3.8 A when connected to 240 V. What is the cost (with electrical energy at 9 cents per kWh) of running the pump for 10 h?

82 cents

If electrical energy costs 5.5 cents per kWh, what does it cost to heat 200 kg water from 15°C to 80°C? (The specific heat of water = 10^3 cal/kg°C and 1.0 cal = 4.186 J.)

83 cents

A light bulb, sold as long-lasting, is rated 100 W at 130 V. The "increased" lifetime comes from using it at 120 V. Assuming negligible change in resistance at the different voltage, what is its power consumption at 120 V?

85 W

If the size of the charge value is tripled for both of two point charges maintained at a constant separation, the mutual force between them will be changed by what factor?

9.0

If a 9.0-V battery, with negligible internal resistance, and an 18-Ω resistor are connected in series, what is the amount of electrical energy transformed to heat per coulomb of charge that flows through the circuit?

9.0 J

We have an initially uncharged hollow metallic sphere with radius of 5.0 cm. I place a small object with a charge of +10 µC at the center of the sphere through a hole in the surface. Find the electric field present at a point 10 cm from the sphere's center. (ke = 8.99 x 10^9Nxm^2/C^2)

9.0x10⁶ N/C

A 6.0 µC charge is placed at the origin and a second charge is placed on the x-axis at x = 0.30 m. If the resulting force on the second charge is 5.4 N in the positive x-direction, what is the value of its charge?

9.0µC

A proton, which moves perpendicular to a magnetic field of 1.2 T in a circular path of radius 0.080 m, has what speed? (qp = 1.6 x 10^-19 C and mp = 1.67 x 10^-27 kg)

9.2 x 10⁶ m/s

A metal wire has a resistance of 10.00 Ω at a temperature of 20°C. If the same wire has a resistance of 10.55 Ω at 90°C, what is the resistance when its temperature is -20°C?

9.69 Ω

A parallel-plate capacitor has dimensions 4.0 cm x 5.0 cm. The plates are separated by a 1.0-mm thickness of paper (dielectric constant k = 3.7). What is the charge that can be stored on this capacitor, when connected to a 1.5-V battery? (ε0 = 8.85 x 10^-12 C^2/Nxm^2)

9.8 x 10 ⁻¹¹ C

The force on a charged particle created by its motion in a magnetic field is maximum at what angle between the particle velocity and field?

90°

Charge A has 10 electric field lines coming out, Charge B has 20 lines coming out, and Charge C has 30 lines coming in. Which pair of these charges will have the largest force between them if placed one cm apart?

B and C

The unit of capacitance, the farad, is dimensionally equivalent to which of the following?

C/V

A proton with initial kinetic energy E is moving in circular motion in a uniform magnetic field. When it has completed one eighth of a revolution, what is its kinetic energy?

E

There is a current I flowing in a clockwise direction in a square loop of wire that is in the plane of the paper. If the magnetic field B is toward the right, and if each side of the loop has length L, then the net magnetic torque acting on the loop is:

IBL²

Three resistors connected in parallel each carry currents labeled I1, I2 and I3. Which of the following expresses the value of the total current IT in the combined system?

It = I₁ + I₂ + I₃

Three resistors connected in series each carry currents labeled I1, I2 and I3. Which of the following expresses the value of the total current IT in the system made up of the three resistors in series?

It = I₁ = I₂ = I₃

What is Kirchhoff's 1st equation for this junction?

I₁ + I₂ + I ₃ = 0

If I1 goes to the right through R1, I2 goes to the right through R2, and I3 goes to the right through R3, what is the resulting equation resulting from applying Kirchhoff's junction rule at point b?

I₁ + I₂ + I₃ = 0

The quantity volt is equivalent to which of the following?

J/C

The unit of electrical potential, the volt, is dimensionally equivalent to:

J/C

Which is a unit of power?

J/s

Two wires with the same resistance have the same diameter but different lengths. If wire 1 has length L1 and wire 2 has length L2, how do L1 and L2 compare if wire 1 is made from copper and wire 2 is made from aluminum? The resistivity of copper is 1.7 x 10^-5 Ω·m and the resistivity of aluminum is 2.82x 10^-5 Ω·m.

L₁ = 1.7 L₂

Who was the first to determine the electron's charge?

Millikan

Electric field is dimensionally equivalent to which of the following?

N/C

The number density of conduction electrons in a metal can be found from the density p of the metal, the mass per mole M of the metal, the number of conduction electrons per metal atom, and Avogadro's number NA. If we assume one conduction electron per atom, which of the following gives the number density of conduction electrons for a given metal?

Nap/M

The constant ke, which appears in Coulomb's law formula, is equivalent dimensionally to which of the following?

N·m²/C²

Magnetism had been a known phenomenon for some time before its relation to electric currents was found. That a current in a wire produces a magnetic field was discovered by:

Oersted

Superconductivity was discovered by:

Onnes

Which two resistors are in parallel with each other?

R2 and R3

Which resistor is in series with resistor R?

R4

Three resistors with values R1, R2 and R3, respectively, are connected in parallel. Which of the following expresses the total resistance,RT, of the three resistors when connected in parallel?

Rt = (1/R₁ +1/R₂ + 1/R₃)⁻¹

Three resistors with values of R1, R2 and R3, respectively, are connected in series. Which of the following expresses the total resistance,RT, of the three resistors?

Rt = R₁ + R₂ + R₃

If R1 < R2 < R3, and if these resistors are connected in parallel in a circuit, which one has the highest current?

R₁

If R1 < R2 < R3, and if these resistors are connected in series in a circuit, which one dissipates the greatest power?

R₃

The unit for rate of energy transformation, the watt, in an electric circuit is equivalent to which of the following?

V.A

The unit of electric resistance, the ohm, is equivalent to which of the following?

V/A

The unit of electric current, the ampere, is equivalent to which of the following?

V/Ω

When charge Q1 is placed at point P1, the resulting potential at point P is V1. When Q2 is placed at point P2 after Q1 is in position at P1, the resulting potential at P becomes V2. What is the potential at point P if charge Q1 is then removed?

V₂-V₁

When current is flowing in a superconductor, which statement is not true?

a battery is needed to keep the current going

A proton moving with a speed of 3.0 x 10^5 m/s perpendicular to a uniform magnetic field of 0.20 T will follow which of the paths described below? (qp = 1.6 x 10^-19 C and mp = 1.67 x 10^-27 kg)

a circular path of 1.6 cm radius

A deuteron, with the same charge but twice the mass of a proton, moves with a speed of 3.0 x 10^5 m/s perpendicular to a uniform magnetic field of 0.20 T. Which of the paths described below would it follow? (qp = 1.6 x 10^-19 C and md = 3.34 x 10^-27 kg)

a circular path of 3.1 cm radius

Electrical charges and magnetic poles have many similarities, but one difference is:

a magnetic pole cannot be isolated

The magnetic pole of the Earth nearest the geographic North Pole corresponds to which of the following?

a magnetic south pole

In which case does an electric field do positive work on a charged particle?

a negative charge moves opposite to the direction of the electric field

Two parallel conductors are carrying currents in the same direction. The currents are non-zero and not necessarily equal. The magnitude of the magnetic field midway between them is 40 T. If one of the currents then has its direction reversed, what is the resulting magnitude of the magnetic field midway between them?

a value greater than 40 µT

The size of the electric current in an electrical conductor is a function of which of the following?

all of the above choices are valid

Which of the following characteristics are held in common by both gravitational and electrostatic forces when dealing with either point masses or charges?

all of the above choices are valid

The term magnetic declination refers to which of the following?

angle between directions to true north and magnetic north

A free electron is in an electric field. With respect to the field, it experiences a force acting:

anti-parallel (opposite in direction)

If a charged particle is moving in a uniform magnetic field, its path can be:

any of the above

The force exerted on a current-carrying wire located in an external magnetic field is directly proportional to which of the following?

both A and B

Which of the following devices makes use of an electromagnet?

both A and B

A current in a solenoid with N turns creates a magnetic field at the center of that loop. The field strength is directly proportional to:

both choices A and B are valid

The direction of the force on a current carrying wire located in an external magnetic field is which of the following?

both choices A and B are valid

A repelling force must occur between two charged objects under which conditions?

charges are of like signs

Which of the following best characterizes electrical insulators?

charges on the surface don't move

The dip angle is:

close to or at zero the equator

Geophysicists today generally attribute the existence of the Earth's magnetic field to which of the following?

convection currents within the liquid interior

The basic function of an electromotive force in a circuit is to do which of the following?

convert some other form of energy into electrical

In the Millikan oil-drop experiment it was found that oil droplets:

could have positive, negative, or zero net charge

Increasing the separation of the two charged parallel plates of a capacitor, which are disconnected from a battery, will produce what effect on the capacitor?

decrease capacitance

The magnetic field of the Earth is believed responsible for which of the following?

deflection of charged cosmic rays

The combination of two separated point charges of opposite sign but equal magnitude is called an electric:

dipole

A circular current loop is placed in an external magnetic field. How is the torque related to the radius of the loop?

directly proportional to radius squared

Which process will double the power given off by a resistor?

doubling the current by making a resistance half as big

A wire is lying horizontally in the north-south direction and the horizontal magnetic field is toward the east. Some positive charges in the wire move north and an equal number of negative charges move south. The direction of the force on the wire will be

down, into the page

When a superconductor's temperature drops below the critical temperature, its resistance:

drops to zero

If a proton is released at the equator and falls toward the Earth under the influence of gravity, the magnetic force on the proton will be toward the:

east

Which of the following best characterizes electrical conductors?

electric charges move freely

The quantity of electrical potential, the volt, is dimensionally equivalent to:

electric field x distance

The beam of electrons that hits the screen of an oscilloscope is moved up and down by:

electrical charges on defelcting plates

Doug rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. What happens?

electrons are added to the rod

When a glass rod is rubbed with silk, which of the following statements best describes what happens?

electrons are removed from the rod

The current in a long wire creates a magnetic field in the region around the wire. How is the strength of the field at distance rfrom the wire center related to the magnitude of the field?

field inversely proportional to r

The number of electric field lines passing through a unit cross sectional area is indicative of:

field strength

A current in a long, straight wire produces a magnetic field. The magnetic field lines:

form circles that go around the wire

The right-hand rule allows one to find a property of the interaction of a magnetic field with a charged particle. The right-hand rule applied to moving charges:

gives the direction of the force on a charge moving in a magnetic field

In applications where electrical shocks may be more likely, such as around water in kitchens and bathrooms, special outlets called GFI's are used. What does GFI stand for?

ground-fault interrupter

Ten coulombs of charge start from the negative terminal of a battery, flow through the battery and then leave the positive terminal through a wire, flow through a resistor and then return to the starting point on this closed circuit. In this complete process, the ten coulombs:

have no net change in potential energy

Inserting a dielectric material between two charged parallel conducting plates, originally separated by air and disconnected from a battery, will produce what effect on the capacitor?

increase capacitance

Increasing the voltage across the two plates of a capacitor will produce what effect on the capacitor?

increase charge

The internal resistances of an ideal voltmeter and an ideal ammeter are respectively (ideal meaning the behavior of the system is not changed when using the meter):

infinite and zero

A proton is released such that its initial velocity is from right to left across this page. The proton's path, however, is deflected in a direction toward the bottom edge of the page due to the presence of a uniform magnetic field. What is the direction of this field?

into the page

Of the following substances, which one contains the highest density of free electrons?

iron

Which of the following is not a hard magnetic material?

iron

Household 120-V outlets are made to accept three-pronged plugs. One of the prongs attaches to the "live" wire at 120 V, and another attaches to the "neutral" wire that is connected to ground. What is the round third prong for?

it connects the case of the appliance directly to ground for safety purposes

When a light bulb is turned on, its resistance increases until it reaches operating temperature. What happens to the current in the bulb as it is warming up?

it decreases

The resistivity of a material is doubled when heated a certain amount. What happens to the resistance of a resistor made of this material when heated the same amount.

it doubles

When an electromagnet has an iron core inserted, what happens to the strength of the magnet?

it increases

A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the power dissipated by it?

it increases by a factor of 2 3/2

A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the current through it?

it increases by a factor of 2½

A soft magnetic material has which property?

it is easy to magnetize

If the current in a wire is tripled, what effect does this have on the electron drift velocity in the wire?

it triples

In a mass spectrometer, an ion will have a smaller radius for its circular path if:

its charge is greater

If two parallel, conducting plates have equal positive charge, the electric field lines will:

leave both plates and go to infinity

At which location will the electric field between the two parallel plates of a charged capacitor be the strongest in magnitude?

midway between the two plated nearest their center

When a magnetic field causes a charged particle to move in a circular path, the only quantity listed below which the magnetic force changes significantly as the particle goes around in a circle is the particle's:

momentum

If body M, with a positive charge, is used to charge body N by induction, what will be the nature of the charge left on the latter?

must be negative

When an electric current exists within a conducting wire, which of the following statements describes the condition of any accompanying electric field?

must be parallel to current flow

If body P, with a positive charge, is placed in contact with body Q (initially uncharged), what will be the nature of the charge left on Q?

must be positive

An ion is released from rest and moves due to the force from an electric field from a position in the field having a potential of 14 V to a position having a potential of 8 V. The ion:

must have a positive charge

A superconducting wire's chief characteristic is which of the following?

no resistance

Two identical balls have the same amount of charge, but the charge on ball A is positive and the charge on ball B is negative. The balls are placed on a smooth, level, frictionless table whose top is an insulator. Which of the following is true?

non of the above is correct

A certain capacitor is charged to 10 V and then, at t = 0, allowed to discharge through a certain resistor. There will be a certain time before the voltage across the capacitor reaches 5 V. This time can be decreased for this circuit by increasing:

none of the above

Consider some material that has been cooled until it has become a superconductor. If it is cooled even further its resistance will:

none of the above

If a certain resistor obeys Ohm's law, its resistance will change:

none of the above, since resistance is a constant for the given resistor

Materials having resistance changes as voltage or current varies are called:

nonohmic

There is a magnetic force on a particle. It is possible that the particle is:

not part of a wire

A proton moves across the Earth's equator in a northeasterly direction. At this point the Earth's magnetic field has a direction due north and is parallel to the surface. What is the direction of the force acting on the proton at this instant?

out of the Earth's surface

Household circuits are wired in ____.

parallel

The electric field at the surface of a positively charged conductor has a direction characterized by which of the following?

perpendicular outward and away from the charge

An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be:

positive

If the distance between two isolated parallel plates that are oppositely charged is doubled, the electric field between the plates is essentially unchanged. However, the:

potential difference between the plates will double

The magnetic domains in a non-magnetized piece of iron are characterized by which orientation?

random

Two parallel conductors each of 0.50 m length, separated by 5.0 x 10^-3 m and carrying 3.0 A in opposite directions, will experience what type and magnitude of mutual force? (magnetic permeability in empty space µ0 = 4π x 10^-7 Tm/A)

repulsive, 1.8 x 10 ⁻⁴ N

The electric field of a point charge has an inverse ____ behavior.

r²

The temperature coefficient of resistivity is a quantity that is:

sometimes negative

A charge, +Q, is placed inside a balloon and the balloon is inflated. As the radius of the balloon r increases the number of field lines going through the surface of the balloon:

stays the same

The path of a charged particle moving parallel to a uniform magnetic field will be a:

straight line

Resistors of values 8.0 Ω, 12.0 Ω, and 24.0 Ω are connected in series across a battery with a small internal resistance. Which resistor dissipates the greatest power?

the 24.0-Ω resistor

Resistors of values 8.0 Ω, 12.0 Ω, and 24.0 Ω are connected in parallel across a fresh battery. Which resistor dissipates the greatest power?

the 8.0 Ω resistor

Which of the following locations has the smallest (in magnitude) magnetic declination?

the South Carolina-Georgia border

I wish to use a positively charged rod to charge a ball by induction. Which statement is correct?

the ball must be a conductor

A light bulb with a tungsten filament is attached to a source of variable voltage. As the voltage is increased on the bulb,

the bulb's resistance increases

How can a charged object attract an uncharged object made of non-conducting material?

the charges in the uncharged object can becomes polarized

A current in a solenoid coil creates a magnetic field inside that coil. The field strength is directly proportional to:

the current

Three resistors, each with resistance R1, are in series in a circuit. They are replaced by one equivalent resistor, R. Comparing this resistor to the first resistor of the initial circuit, which of the following is true?

the current through R equals the current through R₁

If a conductor is in electrostatic equilibrium near an electrical charge:

the electric field inside the conductor must be zero

The Millikan oil-drop experiment demonstrated that:

the electronic charge is quantized

Doubling the voltage across a parallel plate capacitor does not double which of the following?

the energy stored

Consider two charged spheres, one with charge +2 C and the other with -2 C. A proton (a positively charged particle) is at the point halfway between the spheres. What is not zero?

the force on the proton

If a charge +Q is placed inside a hollow isolated conductor that is originally neutral and the charge does not touch that conductor at any time:

the outside surface of the counter will become positively charged

There is a hollow, conducting, uncharged sphere with a negative charge inside the sphere. Consider the electrical potential at the inner and outer surfaces of the sphere. Which of the following is true?

the potentials on both surfaces are equal but not zero

Relative distribution of charge density on the surface of a conducting solid depends on:

the shape of the conductor

When you flip a switch to turn on a light, the delay before the light turns on is determined by:

the speed of the electric field moving in the wire

The electric field associated with a uniformly charged hollow metallic sphere is the greatest at:

the sphere's outer surface

Consider two long, straight parallel wires, each carrying a current I. If the currents are flowing in opposite directions:

the two wires will repel each other

Three resistors, each with resistance R1, are in parallel in a circuit. They are replaced by one equivalent resistor, R. Compare this resistor to the first resistor of the initial circuit. Which of the following statements is true?

the voltage across R equals the voltage across R₁

Which voltage is not caused by a source of emf?

the voltage across a charged capacitor

Two insulated current-carrying straight wires of equal length are arranged in the lab so that Wire A carries a current northward and Wire B carries a current eastward, the wires crossing at their midpoints separated only by their insulation. Which of the following statements are true?

there are forces, but the net force on each wire is zero

A stationary positive charge +Q is located in a magnetic field B, which is directed toward the right as indicated. The direction of the magnetic force on Q is

there is no magnetic force

When charging two objects by rubbing them together:

they must be made of different material

If one doubles the emfs in a circuit and doubles the resistances in the circuit at the same time, what happens to the currents through the resistors? Assume there are only emfs and resistors in the circuit.

they stay the same

Assume that a uniform magnetic field is directed into this page. If an electron is released with an initial velocity directed from the bottom edge to the top edge of the page, which of the following describes the direction of the resultant force acting on the electron?

to the right

A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 x 10^-4 T. What is the direction of the force on the wire?

toward the Earth's surface

Two parallel wires are separated by 0.25 m. Wire A carries 5.0 A and Wire B carries 10 A, both currents in the same direction. The force on 0.80 m of Wire A is:

toward wire B

Wire A and Wire B are each carrying the same current. If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdAin Wire A compare to that in Wire B?

vda = vdb/4

Two charges, +Q and -Q, are located two meters apart and there is a point along the line that is equidistant from the two charges as indicated. Which vector best represents the direction of the electric field at that point?

vector Ea

Which is not a force?

voltage

At what point is the charge per unit area greatest on the surface of an irregularly shaped conducting solid?

where curvature is greatest

Two long parallel wires 20 cm apart carry currents of 5.0 A and 8.0 A in the same direction. Is there any point between the two wires where the magnetic field is zero?

yes, 7.7 cm from the 5-A wire

An electron (charge -1.6 x 10^-19 C) moves on a path perpendicular to the direction of a uniform electric field of strength 3.0 N/C. How much work is done on the electron as it moves 15 cm?

zero

An electron which moves with a speed of 3.0 x 10^4 m/s parallel to a uniform magnetic field of 0.40 T experiences a force of what magnitude? (e = 1.6 x 10^-19 C)

zero

The temperature coefficient of resistivity for a "perfect" ohmic material would be:

zero

There is a current I flowing in a clockwise direction in a square loop of wire that is in the plane of the paper. If the magnetic field B is toward the right, and if each side of the loop has length L, then the net magnetic force acting on the loop is

zero

Two parallel wires are separated by 0.25 m. Wire A carries 5.0 A and Wire B carries 10 A, both currents in the same direction. The force on 0.80 m of Wire A is:

zero

Two point charges each have a value of 30.0 mC and are separated by a distance of 4.00 cm. What is the electric field midway between the two charges? (ke = 8.99 x 10^9 N·m^2/C^2)

zero

Three resistors connected in series have individual voltages labeled ∆V1, ∆V2 and ∆V3, respectively. Which of the following expresses the value of the total voltage ∆VT taken over the three resistors together?

∆Vt = ∆V1 +∆V2 +∆V3

Three resistors connected in parallel have the individual voltages labeled ∆V1, ∆V2 and ∆V3, respectively. Which of the following expresses the total voltage ∆VT across the three resistors when connected in this manner?

∆Vt = ∆V1 = ∆V2 = ∆V3