Physics Test Practice Questions
C
A 4.0-Ω resistor is connected to a 12-Ω resistor and this combination is connected to an ideal dc power supply with voltage V as shown in the figure. If the total current in this circuit is I = 2.0 A, what is the value of voltage V? A. 2.0 V B. 3.0 V C. 6.0 V D. 1.5 V E. 8.0 V
A
A 4000-Ω resistor is connected across a 220-V power source. What current will flow through the resistor? A. 0.055 A B. 1.8 A C. 5.5 A D. 18 A
D
A 6.0-Ω and a 12-Ω resistor are connected in parallel across an ideal 36-V battery. What power is dissipated by the 6.0-Ω resistor? A. 220 W B. 48 W C. 490 W D. 24 W
A, D
A 9-V battery is hooked up to two resistors in series using wires of negligible resistance. One has a resistance of 5 Ω, and the other has a resistance of 10 Ω. Several locations along the circuit are marked with letters, as shown in the figure. Which statements about this circuit are true? (There could be more than one correct choice.) A. The current is exactly the same at points A, B, C, and D B. The current at A is greater than the current at B, which is equal to the current at C, which is greater than the current at D C. The current at A is greater than the current at B, which is greater than the current at C, which is greater than the current at D D. The potential at B is equal to the potential at C E. The potential at D is equal to the potential at C
A
A 9-V battery is hooked up to two resistors in series. One has a resistance of 5 Ω, and the other has a resistance of 10 Ω. Several locations along the circuit are marked with letters, as shown in the figure. Through which resistor is energy being dissipated at the higher rate? A. the 10-Ω resistor B. the 5-Ω resistor C. energy is being dissipated by both resistors at the same rate
A
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 A. increases B. decreases C. remains the same
C
A number of resistors are connected across points A and B as shown in the figure. What is the equivalent resistance between points A and B? A. 4 Ω B. 6 Ω C. 8 Ω D. 10 Ω E. 12 Ω
B
A pair of charged conducting plates produces a uniform field of 12,000 N/C, directed to the right, between the plates. The separation of the plates is 40 mm. An electron is projected from plate A, directly toward plate B, with an initial speed of v = 2.0 x 10^7 m/s. What is the speed of the electron as it strikes plate B? (e = 1.6 x 10^-19 C, melectron = 9.11 x 10^-31 kg) A. 1.2 x 10^7 m/s B. 1.5 x 10^7 m/s C. 1.8 x 10^7 m/s D. 2.1 x 10^7 m/s E. 2.4 x 10^7 m/s
D
A particle with a charge of +4.0 μC has a mass of 5.0 g. What magnitude electric field directed upward will exactly balance the weight of the particle? A. 4.1 x 10^4 N/C B. 8.2 x 10^4 N/C C. 4.4 x 10^4 N/C D. 1.2 x 10^4 N/C
A
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: A. is repelled by the sphere B. is attracted to the sphere C. feels no force due to the sphere
B, C
A proton and an electron are released from rest, with only the electrostatic force acting. Which of the following statements must be true about them as they move toward each other? (There could be more than one correct choice.) A. Their electric potential energy keeps increasing B. Their kinetic energy keeps increasing C. Their electric potential energy keeps decreasing D. Their kinetic energy keeps decreasing E. Their acceleration keeps decreasing
D
A simple circuit has a total resistance of 30 Ω. If a 2.0-A current is maintained in this circuit, how much energy is dissipated in this circuit in 4.0 seconds? A. 24 J B. 4.8 J C. 48 J D. 480 J E. 6.0 J
A
If the voltage across a circuit of constant resistance is doubled, the power dissipated by that circuit will: A. be four times as large B. be two times as large C. decrease to one-half the original power D. decrease to one-fourth the original power
D
As a proton moves in the direction the electric field lines: A. it is moving from low potential to high potential and gaining electric potential energy B. it is moving from low potential to high potential and losing electric potential energy C. it is moving from high potential to low potential and gaining electric potential energy D. it is moving from high potential to low potential and losing electric potential energy E. both its electric potential and electric potential energy remain constant
A
As more resistors are added in parallel across a constant voltage source, the power supplied by the source: A. increases B. decreases C. does not change
E
If two objects are electrically attracted to each other: A. both objects must be negatively charged B. both object must be positively charged C. one object must be positively charged and the other object must be negatively charged D. the objects could be electrically neutral E. None of the above statements are absolutely true
A
Five 2.0-Ω resistors are connected as shown in the figure. What is the equivalent resistance of this combination between points a and b? A. 1.0 Ω B. 10.0 Ω C. 2.0 Ω D. 6.0 Ω E. 0.40 Ω
E
For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material? A. power B. resistivity C. 1/(resistivity) D. resistance E. 1/(resistance)
B
Four resistors are connected across an ideal dc battery with voltage V, as shown in the figure. If the total current in this circuit is I = 1 A, what is the value of the voltage V? A. 2 V B. 4 V C. 6 V D. 8 V E. 10 V
A
Four unequal resistors are connected in a parallel with each other. Which one of the following statements is correct about this combination? A. The equivalent resistance is less than that of the smallest resistor B. The equivalent resistance is equal to the average of the four resistances C. The equivalent resistance is midway between the largest and smallest resistance D. The equivalent resistance is more than the largest resistance E. None of the other choices is correct
E
Four unequal resistors are connected in series with each other. Which one of the following statements is correct about this combination? A. The equivalent resistance is equal to that of any one of the resistors B. The equivalent resistance is equal to average of the four resistances C. The equivalent resistance is less than that of the smallest resistor D. The equivalent resistance is less than that of the largest resistor E. The equivalent resistance is more than the largest resistance
E
If a quantity you calculated has units of A · s, what is that quantity? A. potential B. resistivity C. resistance D. capacitance E. charge A · s = (C/s).s = C)
C
If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will: A. increase by a factor of two B. increase by a factor of four C. decrease to one-half its original value D. decrease to one-fourth its original value
D, E
In outer space, a positive charge q is released near a positive fixed charge Q. As q moves away from Q, what is true about the motion of q? (There may be more than one correct choice) A. It will move with decreasing speed B. It will move with constant acceleration C. It will move with increasing acceleration D. It will move with decreasing acceleration E. It will move with increasing speed
C
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? A. 2.10 m B. 3.67 m C. 3.12 m D. 2.49 m E. 1.13 m
25 Ohms
The graph shown in the figure shows the results of measurements of the dc current through a circuit device for various potential differences across it. Assume that all the numbers shown are accurate to two significant figures. What is the resistance of this device?
D
The length of a certain wire is doubled and at the same time its radius is also doubled. What is the new resistance of this wire? A. It stays the same B. It is 2 times as large C. It is 4 times as large D. It is 1/2 as large E. It is 1/4 as large
D
The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2. What is the new resistance of this wire? A. It is 2 times as large B. It is 4 times as large C. It is 6 times as large D. It is 8 times as large E. It is 1/2 as large
B
The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire? A. It stays the same B. It is 2 times as large C. It is 3 times as large D. It is 4 times as large E. It is 1/2 as large
D
The length of a certain wire is kept same while its radius is doubled. What is the new resistance of this wire? A. It is increased by a factor of 2 B. It is increased by a factor of 4 C. It is reduced by a factor of 2 D. It is reduced by a factor of 4 E. It is reduced by a factor of 8
A
The resistors in the circuit shown in the figure each have a resistance of 700 Ω. What is the equivalent resistance between points a and b of this combination? A. 700 Ω B. 2800 Ω C. 175 Ω D. 1400 Ω
D
The three point charges +4.0 μC, -5.0 μC, and -9.0 μC are placed on the x-axis at the points x = 0 cm, x = 40 cm, and x = 120 cm, respectively. What is the x component of the electrostatic force on the -9.0 μC charge due to the other two charges? A. -0.55 N B. 0.55 N C. 0.64 N D. 0.41 N E. -0.41 N
A
Two equally charged tiny spheres of mass 1.0 g are placed 2.0 cm apart. When released, they begin to accelerate away from each other at 414 m/s^2. What is the magnitude of the charge on each sphere, assuming only that the electric force is present? A. 140 nC B. 120 nC C. 95 nC D. 75 nC
C
Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude F due to the other. With time, charge gradually diminishes on both spheres by leaking off. When each of the spheres has lost half its initial charge, what will be the magnitude of the electrostatic force on each one? A. 1/6 F B. 1/8 F C. 1/4 F D. 1/2 F
E
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? A. 2 N B. 1/2 N C. 1/4 N D. 1/8 N E. 1/16 N
E
Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one? A. It increases by a factor of 2 B. It increases by a factor of √2 C. It is reduced by a factor of √2 D. It increases by a factor of 4 E. It remains the same
A, D
Two protons are fired toward each other in a particle accelerator, with only the electrostatic force acting. Which of the following statements must be true about them as they move closer together? (There could be more than one correct choice.) A. Their electric potential energy keeps increasing B. Their kinetic energy keeps increasing C. Their electric potential energy keeps decreasing D. Their kinetic energy keeps decreasing E. Their acceleration keeps decreasing
B, C, E
Two protons are released from rest, with only the electrostatic force acting. Which of the following statements must be true about them as they move apart? (There could be more than one correct choice.) A. Their electric potential energy keeps increasing B. Their kinetic energy keeps increasing C. Their electric potential energy keeps decreasing D. Their kinetic energy keeps decreasing E. Their acceleration keeps decreasing
C
Two tiny beads are 25 cm apart with no other charges or fields present. Bead A carries 10 μC of charge and Bead B carries 1 μC. Which one of the following statements is true about the magnitudes of the electric forces on these beads? A. The force on A is 10 times the force on B B. The force on B is 10 times the force on A C. The force on A is exactly equal to the force on B D. The force on A is 100 times the force on B E. The force on B is 100 times the force on A
A
Two tiny particles having charges +20.0 μC and -8.00 μC are separated by a distance of 20.0 cm. What are the magnitude and direction of electric field midway between these two charges? A. 25.2 x 10^6 N/C directed towards the negative charge B. 25.2 x 10^6 N/C directed towards the positive charge C. 25.2 x 10^5 N/C directed towards the negative charge D. 25.2 x 10^5 N/C directed towards the positive charge E. 25.2 x 10^4 N/C directed towards the negative charge
B
What current flows from the battery in the circuit shown in the figure? The battery is ideal, and all the numbers are accurate to two significant figures. A. 0.35 A B. 2.0 A C. 2.5 A D. 3.0 A
A
What current is flowing in a wire if 0.67 C of charge pass a point in the wire in 0.30 S? A. 2.2 A B. 0.67 A C. 0.30 A D. 0.20 A
B
What is the magnitude of the potential difference between points C and D for the circuit shown in the figure? A. 6.0 V B. 4.0 V C. 3.0 V D. 2.0 V
B
What is the resistance of a 0.100-kW light bulb designed to be used in a 120-V circuit dc? A. 12.0 Ω B. 144 Ω C. 1.2 Ω D. 0.83 Ω
B
What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A? A. 100 V B. 25 V C. 4.0 V D. 1.0 V
D
What potential difference is required to cause 4.00 A to flow through a resistance of 330 Ω? A. 12.1 V B. 82.5 V C. 334 V D. 1320 V
D
When 1.0-μC point charge is 15 m from a second point charge, each one experiences a force of 1.0 μN. What is the magnitude of the second charge? A. 25 C B. 1.0 C C. 10 nC D. 0.025 C E. 25 nC
B
When a current flows through a metal wire, the moving charges are: A. only protons B. only electrons C. both protons and electrons D. positive metal ions E. negative metal ions
B
When unequal resistors are connected in parallel in a circuit: A. the same current always runs through each resistor B. the potential drop is always the same across each resistor C. the largest resistance has the largest current through it D. the power generated in each resistor is the same
C
Which one of the following quantities is equivalent to 1 W? (P = IV) A. 1 V/A B. 1 Ω · m C. 1 V · A D. 1 V/Ω E. 1 A · s