Phy 112 Test 1 Quizes

What is the net charge on an object that has gained 8 x 10^13 electrons?

-1.3 x 10^-5 C

A 9.0V battery connects to a wire resistor. The wire resistor is tungsten (ρ = 5.6 x 10-8 Ω-m) 0.5 m long, has a radius of 1.2 x 10-5 m. What is the current through the resistor?

0.15 A

What is the current in a wire if 4 x 1018 electrons flow through the wire every 3 sec?

0.21 A

What is the current in a wire if 4 x 10^18 electrons flow through the wire every 3 seconds?

0.21A

A 1.5V battery connects to a 10 Ω resistor. The power dissipated by the resistor is

0.23 W

A 1.5V battery connects to a 10ohm resistor. The power dissipated by the resistor is?

0.23W

How much energy does it take to move a particle with a charge of +2 nC, from an initial position infinitely far from a second particle with a charge of +3 mC, to a final position 0.20 m from the second particle?

0.27 J

How much energy does it take to move a particle with a charge of +2nC, from an initial position infinitely far from a second particle with a charge of +3mC, to a final position 0.20m from the second particle?

0.27J

Two charged particles, each with a charge of +8.0 μC are at some position near each other. What is the distance between the particles if the static electric force between them is 5.0 N?

0.34 M

Two charged particles, each with a charge of +8.0uC are at some position near each other. What is the distance between the particles if the static electric force between them is 5.0N?

0.34m

Three charged particles are held in place. Particle A has a net charge of +2 μC and is at (0, 0) m. Particle B has a net charge of -4 μC and is placed a (0.5, 0) m. Particle C has a net charge of -4 μC and is at (0, 0.5) m. What is the magnitude of the net force on particle A?

0.41N

How much energy will an electron gain if it moves through a potential difference of 1.0 V?

1 eV

How much energy will an electron gain if it moves through a potential difference of 1.0V?

1.0eV

A battery connects to a resistor. The rate of energy dissipated by the resistor is 1.44 W. The rate of energy supplied by the battery is

1.44 W

What is the strength of an electric field measured 0.5 m from a point source with a net charge of 5.0 μC?

1.8 x 10^5 N/C

What is the strength of an electric field measured 0.5m from a point source with a net charge of 5.0uC?

1.8 x 10^5 N/C

Charged particles A and B experience a static electric force of F. If the distance between the charge particles triples, then the static electric force becomes?

1/9F

A particle with a mass of 0.01 kg and a net charge of -0.05 C accelerates from rest through a uniform electric field. If the strength of the field is 2000 V/C, what is the speed of the particle after traveling for 0.5 m?

100 m/s

A particle with a mass of 0.01kg and a net charge of -0.05C accelerates from rest through a uniform electric field. If the strength of the field is 2000 V/C, what is the speed of the particle after traveling for 0.5m?

100m/s

Three charged particles are held in place. Particle A has a net charge of +2uC and is at (0 , 0)m. Particle B has a net charge of +4uC and is placed at (0.5 , 0)m. Particle C has a net charge of -4uC and is placed at (0 , 0.5)m. What is the angle of direction of the net force acting on particle A?

135 degrees

A particle with a net charge of -2 μC is halfway between two particles with a net charge of +4 μC and +6 μC, respectively. The two positively charged particles are 10 cm apart. What is the magnitude of the net force on the negative particle?

14.4 N

A particle with a net charge of -2uC is halfway between two particles with a net charge of +4uC and +6uC, respectively. The two positively charged particles are 10cm apart. What is the magnitude of the net force on the negative particle?

14.4N

An electron moves through a potential difference of 1500 V. The magnitude of the change in potential energy experienced by the electron is

1500 eV because 1 eV = 1 Volt

An electron moves through a potential difference of 1500V. The magnitude of the change in potential energy experienced by the electron is?

1500eV

Use the following voltage versus current data to determine the resistance of a particular resistor. (picture in lesson 5)

16 ohms (rise over run of entire system!!)

Two charged parallel plates have a uniform field strength of 1200N/C between them. If the separation distance between the plates is 0.15m, what is the potential difference between the plates?

180V

How much energy does it take to move a particle with a charge of +6.0 μC a distance 0.5 m through a uniform electric field with a strength of 700 N/C?

2.1x10^-3 J

Four point charges form a square 1.0 m on each side (see below). What is the potential at a point in the center of the square of the value of q is 2 nC? (bottom right is +2q) all 1 meter apart top are -q and bottom is +

25.4 V

A wire carries 8 A of current directed to the left. What is the magnitude of the initial force on a +6 mC charged particle that is moving at a speed of 2000 m/s to the left at a distance 6.0 mm from the wire?

3.2 x 10^-3 N

Wall outlets in Australia provide a peak voltage of 338 V. What is the RMS current through a device that has an average power rating of 800 W?

3.3 A

How many electrons will flow through a wire in 2.0min if the current is 0.5amps?

3.8 x 10^20 electrons

Consider a uniform electric field of 50 N/C directed towards the east. If the potential measured at some point in the field is 80 V, what is the potential at a position 1.0 m directly east of that point?

30 V

Two positively charged particles experience a static electric force of F. One of the particles is replaced with a new charged particle that has three times more charge than the original. The new static electric force will be?

3F

A student takes 5 min to blow dry hair with a 2300 W blow dryer. How much energy dissipates by the blow dryer during this time?

690000 J

Charged particles are at the corners of equilateral triangles, which all have the same area. Rank the magnitude of the electric field strength at point P in each triangle from greatest to least. (picture in lesson 3)

A = B = D > C

Four equal positive charges move through a uniform electric field as shown below. Which of the following correctly ranks the energy GAINED by the particles from greatest to least? (picture in lesson 3)

A = D > B > C

Based on the plot of equipotentials shown in the example below, order the magnitude of the electric field strength at points A, B, and C (from greatest to least). (picture in lesson 3)

A > B > C

Which of the following is an accurate example of charging by induction?

A student brings a charged rod near a block of metal. The student taps the block of metal with a hand and then removes the charged rod.

Which device would cost more to run continuously for 1 hr?

A television that uses a 120V potential difference to draw 1.25A of current.

Which of the following statements regarding charge is most accurate?

All of the above are accurate.

Which of the following is an example of an insulator?

All of the above are examples of insulators. Plastic and glass basically anything that's not a metal.

A wire carries 30 A of current directed to the left. What is the initial magnitude and direction of the force on a +4.0 mC charged particle that is initially moving at a speed of 1000 m/s to the left at a distance 2.0 mm above the wire?

B = 0.003 T (into the page from wire) F = 0.012 N (Downwards or onto the wire is the force)

3. Two 2.0 m long horizontal parallel wires are placed 2 cm apart. The top wire carries 4 A of current to the right, and the bottom wire carries 8 A of current to the left. Do the wires attract or repel? By how much force? (Do bottom wire to top)

B = 8E-5 T (directed into the page) F = 8E-4 N (directed upwards, the wires will repel)

Which of the following correctly shows the equipotentials near a negative point source? (picture in lesson 3)

C

The property of matter that is responsible for static electric effects is?

Charge

Which of the following statements best describes conductors?

Conductors are metal and allow charge to move freely through them. They are good at allowing charge to flow.

The unit used to measure quantity of charge is the?

Coulomb

Which of the following correctly indicates the result of cutting the following permanent magnet in half along the dotted line as shown below?

Each half will have both north and south poles. They will turn into mini magnets.

Which of the following statements regarding equipotentials and electric fields is accurate?

Electric field lines are perpendicular to equipotential lines.

Which statement regarding electric potential is not accurate?

Electric potential depends on the amount of charge on a particle in an electric field.

The electronvolt is a unit that measures?

Energy

The purpose of a battery in a circuit is to act as a source of?

Energy

A battery connects to a resistor. The rate of energy dissipated by the resistor is 1.44W. The rate of energy supplied by the battery is?

Equal to 1.44W

Two charged particles each with a net charge of -q are a distance r apart. The electric force F is measured. The distance between the particles then doubles to 2r, and the amount of charge on both charges doubles to -2q. Relative to the original force, what is the new electric force?

F

What is the force per length ratio on a wire that has 4.0 A of current perpendicularly oriented to a uniform magnetic field of 0.1 T? (good MCAT question)

F/L = 0.4 N/m

Which of the following statements regarding static electric charge is most accurate?

Force is proportional to the inverse square distance between the charged particles.

A negatively charged particle moves through various electric fields. Which of the following correctly indicates whether the negatively charged particle gained or lost energy in each of the following examples? (picture in lesson 3)

Gained energy (- particle from positive plate to + plate), Lost energy (high point source to low point source), Gained energy (Electron jumping a subshell ... light)

When drawing the equipotential 3D maps, positive point sources will form?

Hills

A +3 mC particle with a mass of 3x10-3 g is accelerated to the right a distance of 12 cm from rest through a uniform electric field with a field strength of 4000 N/C. The particle then enters a new uniform field with a field strength of 2000 N/C directed downwards. What is the strength and direction of the magnetic field needed in order for the particle to pass through the electric field undeflected?

Hint: Ue = K & FB - Fe = 0 v = 980 m/s B = 2.0 T

A student decides to build a rail gun. She connects two parallel bars spaced 6 cm apart to a 12 V source, and sets an aluminum bar across the two bars. The student uses a series of neodymium magnets to create a reasonably uniform 1.25 T magnetic field. If the internal resistance of the system is 2 Ω, what is the magnetic force on the aluminum bar?

I = 6 A F = 0.45 N

A student claims that a 60W incandescent light bulb and a 15W CFL light bulb are equally bright (i.e., produce roughly the same amount of light each second). This is because?

In addition to producing light, the incandescent bulb also dissipates ore heat than the CFL.

What adjustments could be made to the system to increase the maximum torque?

Increase the number of loops. Increase the current. Increase the size/Area of the loops Increase the strength of the magnetic field.

An electron moving to the right at a constant speed moves into an electric field. The electric field is to the left. Which of the following correctly indicates how the field will affect the electron's motion?

It will speed up

Point x is equidistant from two particles with net charges of +q and -q of equal magnitude. If a negative point charge is at the position marked by an x, the direction of the net electrical force on the negative point charge is? (picture in lesson 1)

Left

The nucleus of an atom is composed of protons and electrons.

Neutrally charged atoms contain equal amounts of protons and electrons.

A battery connects to a resistor with resistance R, and the resulting current is measured. The resistor is removed, and a new resistor with a resistance of 2R is added. As a result,

None of the above options are correct. (Voltage and Resistance are not related) this goes to show this.

Which of the following processes will NOT result in a change in net charge on an object?

Polarization

Equipotentials are best defined as?

Positions in an electric field where multiple positions have the same voltage.

An electroscope is a device that has small gold foil strips suspended from a metal rod. A student brings a negatively charged rod near the top of a neutral electroscope. The student then briefly touches a hand to the top of the electroscope before removing the charged rod. The foil strips of the electroscope now spread apart. The student then brings a different rod near the top of the electroscope. The leaves of the electroscope move closer together (see below). The new rod is most likely to have a net charge that is?

Positive

Which statement regarding voltage is most accurate?

Positive voltages occur near positive point sources, and negative voltages occur near negative point sources.

A circuit with 20 V battery and two series resistors (1st 10, 2nd 15 ohms). Solve for Current in the battery, current in each resistor, voltage across each resistor, power rating at 2nd resistor.

R = 25 Ω I = 0.80 A (Battery) Series Resistor = same current V = 8.0 V and V = 12.0 V P = 9.6 W

A circuit with 20 V battery and two parallel resistors (1st 10, 2nd 15 ohms). Solve for Current in battery, current in each resistor, voltage across each resistor, power rating at 2nd resistor.

R = 6 Ω I = 3.3 A Parallel Resistor = same voltage drop I = 2 A and I = 1.3 A P = 26.7 W

Two resistors, A and B, individually connect to a 9V battery. A student notices that resistor A is warmer than resistor B. Which resistor has the greatest resistance?

Resistor B has the greatest resistance.

Two +2C charges are placed at two of the vertices of an equilateral triangle. What is the direction of the net electric field at point p? (picture in lesson 3)

Right

An electroscope is a device that has small gold foil strips suspended from a metal rod. If the electroscope is negatively charged, the foil strips will repel and separate from each other (see below). If you bring a negatively charged rod near the top of a negatively charged electroscope, the foil strips will?

Separate further

The diagram below shows the electric field lines and the equipotentials near a point source. Which of the following statements accurately describes the diagram? (picture in lesson 3)

The arrows represent the direction of the electric field, the circles represent positions with equal potential, and the source charge is negative.

A positively charged plastic ballon filled with air will stick to a neutrally charged nonmetal ceiling. Which of the following is the most likely explanation for this behavior?

The ballon caused the ceiling to polarize, which created a net attracting force between the polarized ceiling and the ballon.

A positively charged plastic balloon filled with air will stick to a neutrally charged nonmetal ceiling. Which of the following is the most likely explanation for this behavior?

The balloon caused the ceiling to polarize, which created a net attracting force between the polarized ceiling and the balloon. This is the turboelectric effect.

A battery with a potential difference of V connects to a resistor, and the resulting current is measured. You remove the battery, and a new battery with a potential difference of 2V is put in its place. As a result?

The current will double.

The following diagram is best described as? (picture in lesson 3)

The electric field near two positive point charges.

An electron moves from a position next to a negatively charged source to a position next to a positively charged source (see below). Which statement is accurate? (picture in lesson 5)

The electron will lose energy and move to a higher potential.

An electron moves from a position next to a negatively charged source to a position next to a positively charged source (see below). Which statement is accurate? (two point sources and electron going from - one to + one) (picture in lesson 3)

The electron will lose energy and move to a higher potential.

Which of the following explains why international travelers need to use special adapters when plugging a device designed to operate in the U.S. into a wall outlet in Europe (i.e., V(rms) in the U.S. is 120V, while V(rms) in Europe is 240V)?

The increased voltage causes an increase in power usage, and the device will overheat.

Which of the following correctly identifies the initial direction of the loop's rotation? (B is right, Current goes up on right loop)

The left side of the loop will move out of the screen, while the right side of the loop will move into the screen.

The U.S. has an alternating current frequency of 60Hz. China has an alternating current frequency of 50Hz. This means that?

The number of times voltage cycles in a minute in the U.S. is greater than the number of times voltage cycles in China.

Two charged particles both have positive net charges. They are near each other and released from rest. Which of the following statements best describes the interaction of the particles?

The particles will repel. As they get further apart, the repelling force will decrease.

Electric potential is...?

The ratio of energy per amount of charge on a particle in an electric field. It is predicting what positions are most likely to result in large amounts of electric potential energy when a positive charge is placed at that position. When a low voltage is 0 which is the negative plate and the further it gets away the better voltage. Doesn't care about particle charge.

Which of the following statements concerning charge is most accurate?

The total charge present in the system and surroundings is constant in any process. A charge is not created or destroyed and it comes from a proton or an electron.

Rule for currents in a parallel resistor (Important)

The total current through the battery is equal to the sum of the currents through each resistor. subtract: I battery = I resistor 1 + I resistor 2

Point x is equidistant from two particles with net charges of +q and -q of equal magnitude. If a negative point charge is at the position marked by the x, the direction of the net electrical force on the negative point charge is...? Lesson #1 Image

Up

Two identical batteries, each with a voltage of V, connect to each other in parallel. This arrangement then connects to a resistor (see below). The voltage across the resistor is

V

Current is caused by?

Voltage difference

Wire resistor A has twice the length and twice the cross sectional area of wire resistor B. Which of the following accurately compares the resistances of wire resistors A and B?

Wire A has the same resistance as wire B.

A positive particle begins at a position near a negative plate and ends at a position near a positively charge plate. Which statement is most accurate?

Work is done on the particle so that the particle will end with more energy.

A light bulb connects to a battery. A second, identical light bulb connects in parallel to the first light bulb (see below). The connecting wires have negligible resistance. When the switch is closed, the original light bulb will

experience no change in brightness (Same current = same voltage)

The definition of current is the

flow rate of charge through some point @ a specific time

A positively charged 4 mC particle moving upwards at a speed of 200 m/s enters a 3.5 T field directed into the page. The particle path curves with a radius of 10 cm. What is the mass of the particle?

m = 7E^-6 kg

A charged particle moving at a speed of 40 m/s to the right enters a 1.5 T magnetic field directed upwards (i.e., up the page). The particle experiences a force of 3.0 mN out of the page. What is the charge on the particle?

q = 5E^-5 C Using the right-hand rule, the charge must be positive.

The purpose of a resistor in a circuit is to

restrict the flow of charge by causing charge to hit each other in which energy i released as heat (resistors are very hot)

Solve for the maximum torque on a set of 20 square loops that are 2 cm on each side if they experience a current of 1.0 A in a field of 2 T.

τ = 0.016 N-m (very tiny torque)