Physics Semester Final 2
A battery maintains the electrical potential difference of 6.0-V between two large parallel metal plates separated by 1.0 mm. What is the strength of the electric field between the plates?
6000 V/m
Three charges with equal magnitude but varying signs are at three of the corners of a square of side d. A fourth charge +Q of equal magnitude is at the center of the square as shown in the figure. Which one of the arrows shown represents the net force acting on the charge at the center of the square (Refer to Image - 2 Positives, One Negative)?
A
The type of electricity we get from wall sockets. It travels back and forth.
AC
Charges with opposite charges do what?
Attract
If a south pole and a north pole of two magnets come together what will happen to them?
Attract
Three equal charges +Q are at three of the corners of a square of side d. A fourth charge +Q of equal magnitude is at the center of the square as shown in the figure. Which one of the arrows shown represents the net force acting on the charge at the center of the square (Refer to Image - 3 Positives).
B
If we double the resistance in a circuit but keep the current in it constant, the power dissipated by that circuit will...
Be two times as great.
If you were to cut a small permanent bar magnet in half...
Each piece would in itself be a smaller bar magnet with both north and south poles.
What charge does a neutron have?
Neutral
A flat coil is in a uniform magnetic field. The magnetic flux through the coil is greatest when the plane of its area is?
Perpendicular to the magnetic field.
A negatively-charged plastic rod is brought close to (but does not touch) a neutral metal sphere that is connected to ground. After waiting a few seconds, the ground connection is removed (without touching the sphere), and after that the rod is also removed. The sphere is now...
Positively Charged
If the secondary coil of a transformer contains more loops than the primary coil, then it is a?
Step-Up Transformer
When unequal resistors are connected in series across an ideal battery...
The current flowing in each is the same.
When unequal resistors are connected in parallel in a circuit...
The potential difference is always the same across each resistor.
An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. Which of the following statements are true just before they are about to collide?
They are closer to the initial position of the proton that to the initial position of the electron.
Electrically neutral objects cannot exert an electrical force on each other, but they can exert a gravitational force on each other.
True
Hans Christian Oersted discovered that a magnetic field is produced when a current flows through a wire (True or False)?
True
Hans Christian Oersted was the scientist who accidentally discovered the connection between electricity and magnetism.
True
A small styrofoam ball of mass 0.120 g is placed in an electric field of 6000 N/C pointing downward. What excess charge must be placed on the ball for it to remain suspended in the field?
-196 nC
Four point charges of magnitude 6.00 μC and are at the corners of a square 2.00 m on each side. Two of the charges are positive, and two are negative. What is the electric potential at the center of this square, relative to infinity, due to these charges? (k = 1/4πε0 = 8.99 × 10^9 N •m^2/C^2)
0 V
A 4000-Ω resistor is connected across a 220-V power source. What current will flow through the resistor?
0.055 A
Three point charges are located on the x-axis at the following positions: Q1 = +2.00 μC is at x = 1.00 m, Q2 = +3.00 μC is at x = 0.00, and Q3 = -5.00 μC is at x = -1.00 m. What is the magnitude of the electric force on Q2? (k = 8.99 × 10^9 N • m^2/C^2)
0.189 N
An ideal solenoid 20 cm long is wound with 5000 turns of very thin wire. What strength magnetic field is produced at the center of the solenoid when a current of 10 A flows through it? (μ0 = 4π × 10^-7 T • m/A)
0.31 T
A 120-m long metal wire having a resistivity of 1.68 × 10^-8 Ω • m has a resistance of 6.0 Ω. What is the diameter of the wire?
0.65 mm
How much energy does a 100-W light bulb use in 8.0 hours?
0.80 kWh
Which one of the following quantities is equivalent to 1 W?
1 V • A
Which one of the following quantities is equivalent to 1 Ω?
1 V/A
A piece of plastic has a net charge of +2.00 μC. How protons does this piece of plastic have? (e = 1.60 × 10^-19 C)
1.25 × 10^13
An ideal solenoid of length 10 cm consists of a wire wrapped tightly around a wooden core. The magnetic field strength is 4.0 T inside the solenoid. If the solenoid is stretched to 25 cm by applying a force to it, what does the magnetic field become?
1.6 T
How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0¢/kWh?
1.6¢
Two point charges each experience a 1-N electrostatic force when they are 2 cm apart. If they are moved to a new separation of 8 cm, what is the magnitude of the electric force on each of them?
1/16 N
A resistance heater is rated at 1200 W when operating at 110 V dc. What current will it draw?
11 A
An ideal solenoid that is 34.0 cm long is carrying a current of 2.00 A. If the magnitude of the magnetic field generated at the center of the solenoid is 9.00 mT, how many turns of wire does this solenoid contain? (μ0 = 4π × 10^-7 T • m/A).
1220
How much work is needed to carry an electron from the positive terminal to the negative terminal of a 9.0-V battery. (e = 1.60 × 10^-19 C , melectron = 9.11 × 10^-31 kg)
14.4 × 10^-19 J
A small object with a 5.0-μC charge is accelerating horizontally on a friction-free surface at 0.0050 m/s^2 due only to an electric field. If the object has a mass of 2.0 g, what is the magnitude of the electric field?
2.0 N/C
Two tiny particles carrying like charges of the same magnitude are 0.001m apart. If the electric force on one of them is 5.0 N, what is the magnitude of the charge on each of these particles?(k = 8.99 × 10^9 N • m^2/C^2)
2.4 × 10^-8 C
A high power line carries a current of 1.0 kA. What is the strength of the magnetic field this line produces at the ground, 10 m away? (μ0 = 4π × 10^-7 T • m/A)
20 µT
What charge accumulates on the plates of a 2.0-μF air-filled capacitor when it is charged until the potential difference across its plates is 100 V?
200μC
A transformer has 200 coils in the primary and 400 in the secondary. A voltage of 12V goes into the primary, what is the voltage that comes out?
24v
What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A?
25 V
A kilowatt-hour is equivalent to...
3,600,000 J
The force of attraction that a -40.0 μC point charge exerts on a +108 μC point charge has magnitude 4.00 N. How far apart are these two charges? (k = 8.99 × 10^9 N • m^2/C^2)
3.12 m
An air-filled capacitor has a potential difference between the plates of 80 V. If the charge on each of the plates of the capacitor has magnitude 8.0 μC, what is the electrical energy stored by this capacitor?
320 µJ
A transformer is made of 35 primary coils and 560 secondary coils. If a current with a potential difference of 220v comes into the transformer, what comes out?
3520v
If a charge generator builds a negative static charge of -7.00 how many electrons are transferred to it during this process. (e = 1.60 × 10^-19 C)
4.38 × 10^13
A long straight wire carrying a 4-A current is placed along the x-axis as shown in the figure. What is the magnitude of the magnetic field at a point P, located at y = 2 cm, due to the current in this wire? (μ0 = 4π × 10^-7 T • m/A) - (Refer to Image).
40 μT
The electric potential at a distance of 4 m from a certain point charge is 200 V relative to infinity. What is the potential at a distance of 2 m from the same charge?
400 V
If the power rating of a 400-Ω resistor is 0.80 W, what is the maximum current it can safely draw?
45 mA
In an ideal transformer, how many turns are necessary in a 110-V primary if the 24-V secondary has 100 turns?
458
How much charge must pass by a point in a wire in 10 s for the current inb the wire to be 0.50 A?
5.0 C
When the magnitude of the charge on each plate of an air-filled capacitor is 4 μC, the potential difference between the plates is 80 V. What is the capacitance of this capacitor?
50 nF
What is the equivalent resistance in the circuit shown in the figure (Refer to Image)?
50 Ω
How many electrons are necessary to produce 1.0 C of negative charge? (e = 1.60 × 10^-19 C)
6.3 × 10^18
A light bulb operating at a dc voltage of 120 V has a resistance of 200 Ω. How much power is dissipated in this bulb?
72 W
A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?
78.6 Ω
What is the charge on 1.0 kg of protons? (e = 1.60 × 10^-19 C, mproton = 1.67 × 10^-27 kg)
9.6 × 10^7 C
Three charges with equal magnitude but varying signs are at three of the corners of a square of side d. A fourth charge +Q of equal magnitude is at the center of the square as shown in the figure. Which one of the arrows shown represents the net force acting on the charge at the center of the square (Refer to Image - 3 Negatives)?
A
Three equal positive point charges +q are placed at the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the center of the square (Refer to Image)?
A
Which one of the arrows shown in the figure best represents the direction of the electric field between the two uniformly charged metal plates (Refer to Image)?
A
Three equal negative point charges -q are placed at three of the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the vacant corner of the square (Refer to Image - One With Arrow Pointing Out)?
B
Identical ideal batteries are connected in different arrangements to the same light bulb, as shown in the figure. For which arrangement will the bulb shine the brightest (Refer to Image)?
C
Three equal negative point charges -q are placed at three of the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the center of the square (Refer to Image)?
C
A horizontal wire carries a current straight toward you. From your point of view, the magnetic field caused by this current...
Circles the wire in a counter-clockwise direction.
The safety device that is made to switch off current in a circuit if the load is too much is called a?
Circuit Breaker
The type of electricity we get from batteries. It only travels in one direction.
DC
As more resistors are added in series to a constant voltage source, the power supplied by the source...
Decreases
When you double the number of windings in an ideal solenoid while keeping all other parameters (radius, length and current) fixed, the magnetic field at the center of the solenoid will...
Double
The electric field at point P due to a point charge Q a distance R away from P has magnitude E. In order to double the magnitude of the field at P, you could...
Double the charge to 2Q.
We observe that a moving charged particle experiences no magnetic force. From this we can definitely conclude that...
Either no magnetic field exists or the particle is moving parallel to the field.
According to Lenz's law, the induced current in a circuit always flows to oppose the external magnetic field through the circuit (True or False?)
False
True or False: A transformer is a device to ensure that will shut off if the proper current traveling through a wire is too high.
False
True or False: Like charges will attract.
False
True or False: Like poles of a magnet attract.
False
In the figure, a bar magnet moves away from the solenoid. The direction of the induced current through the resister R is (Refer to Image)?
From a to b.
This is a safety feature that when the current gets too high, it will melt the metal strip itself.
Fuse
A device that converts mechanical energy into electrical energy is called a?
Generator
A transformer is used to?
Increase or decrease an AC voltage.
A hydrogen atom consists of a proton and an electron. If the orbital radius of the electron increases, the electric potential energy of the electron due to the proton...
Increases
As more resistors are added in parallel across a constant voltage source, the power supplied by the source...
Increases
Over ordinary temperature ranges, the resistance of most metals such as copper...
Increases as the metal gets hotter.
Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at a point exactly between the two wires...
Is Zero
A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod...
Is repelled by the sphere.
As an electron moves in the direction the electric field lines...
It is moving from high potential to low potential and gaining electric potential energy.
As a proton moves in the direction the electric field lines...
It is moving from high potential to low potential and losing electric potential energy.
Two point charges, q1 and q2, are separated by a distance R. If the magnitudes of both charges are halved and their separation is also halved, what happens to the electrical force that each charge exerts on the other one?
It remains the same.
In outer space, a positive charge q is released near a positive fixed charge Q, as shown in the figure. As q moves away from Q, what is true about the motion of q (Refer to Image)
It will move with decreasing acceleration.
A device that converts electrical energy into mechanical energy is a?
Motor
What charge does an electron have?
Negative
When a current flows through a metal wire, the moving charges are...
Only Electrons
A transformer is device that normally?
Operates only on AC.
Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The wire on your right carries current directly toward you, and the wire on your left carries current directly away from you. From your point of view, the magnetic field at a point exactly midway between the two wires...
Points Downward
What charge does a proton have?
Positive
Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the radius of the solenoid is doubled to 2b, but all the other quantities remain the same, the magnetic field inside the solenoid will...
Remain the Same
If two north poles of magnets come together what will happen to the magnets?
Repel
Two uncharged metal spheres, #1 and #2, are mounted on insulating support rods. A third metal sphere, carrying a positive charge, is then placed near #2. Now a copper wire is momentarily connected between #1 and #2 and then removed. Finally, sphere #3 is removed. In this final state...
Sphere #1 carries positive charge and #2 carries negative charge.
A transformer is made of 35 primary coils and 560 secondary coils. What type of transformer is it?
Step Up
If the primary coil of transformer contains more loops than the secondary coil, then it is a?
Step-Down Transformer
In the right hand rule for the magnetic field of a magnet what do your fingers coiling represent?
The direction of field lines.
In the right hand rule for the magnetic field of a magnet what does the direction of your thumb represent?
The direction of the current.
A hydrogen nucleus, which has a charge +e, is situated to the left of a carbon nucleus, which has a charge +6e. Which statement is true?
The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is equal to the force exerted on the carbon nucleus.
Four unequal resistors are connected in a parallel with each other. Which one of the following statements is correct about this combination?
The equivalent resistance is less than that of the smallest resistor.
Four unequal resistors are connected in series with each other. Which one of the following statements is correct about this combination?
The equivalent resistance is more than the largest resistance.
Which one of the following statements is correct?
The north pole of a magnet points towards Earth's geographic north pole.
A region of space contains a uniform electric field, directed toward the right, as shown in the figure. Which statement about this situation is correct (Refer to Image)?
The potential at points A and B are equal, and the potential at point C is lower than the potential at point A.
When different resistors are connected in parallel across an ideal battery, we can be certain that...
The potential difference across each is the same.
A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?
The sphere near the charged rod becomes positive and the other one becomes negative.
A long, straight, horizontal wire carries current toward the east. A proton moves toward the east alongside and just south of the wire. What is the direction of the magnetic force on the proton?
Toward the North
An electron is initially moving to the right when it enters a uniform electric field directed upwards, as shown in the figure. Which trajectory (X, Y, Z, or W) will the electron follow in the field (Refer to Image)?
Trajectory Z
Michael Faraday discovered that when you pass a magnet through a coil of wire a current is made in the wire (True or False?)
True
True or False: Electric field lines will flow from positive charge to negative charge.
True
True or False: Opposite charges will attract.
True
X and Y are two initially uncharged metal spheres on insulating stands, and they are in contact with each other. A positively charged rod R is brought close to X as shown in part (a) of the figure. Sphere Y is now moved away from X, as shown in part (b). What are the final charge states of X and Y (Refer to Image)?
X is negative and Y is positive.
A 2.0-m straight wire carrying a current of 0.60 A is oriented parallel to a uniform magnetic field of 0.50 T. What is the magnitude of the magnetic force on it?
Zero
