Question 1

If I = 2.0 A in the circuit segment shown below,what is the potential difference VB − VA?

Accepted Answer

A) +10 V 
B) −20 V 
C) −10 V 
D) +20 V 
E) +30 V 
A) +10 V 
B) −20 V 
C) −10 V 
D) +20 V 
E) +30 V C

Question 2

At t = 0 the switch S is closed with the capacitor uncharged.If C = 50 μF,ε = 20 V,and R = 4.0 kΩ,what is the charge on the capacitor when I = 2.0 mA?

Accepted Answer

A) 360 μC 
B) 480 μC 
C) 240 μC 
D) 600 μC 
E) 400 μC 
A) 360 μC 
B) 480 μC 
C) 240 μC 
D) 600 μC 
E) 400 μC D

Question 3

The circuit below contains three 100-W light bulbs and a capacitor.The emf is 110 V and the capacitor is fully charged.Which light bulb(s)is(are)brightest?

Accepted Answer

A) A 
B) B 
C) C 
D) A and B 
E) A and C 
A) A 
B) B 
C) C 
D) A and B 
E) A and C B

Question 4

What is the potential difference VB − VA when I = 0.50 A in the circuit segment shown below?

Accepted Answer

A) +28 V 
B) +2.0 V 
C) −28 V 
D) −2.0 V 
E) +18 V 
A) +28 V 
B) +2.0 V 
C) −28 V 
D) −2.0 V 
E) +18 V

Question 5

When a capacitor is fully charged,the current through the capacitor in a direct-current circuit is

Accepted Answer

A) zero. 
B) at its maximum value. 
C) equal to the current in a resistive circuit in parallel with the capacitor circuit. 
D) greater than the current in a resistor that is farther from the battery than the capacitor. 
E) zero if it is the only capacitor,but maximum if there is another capacitor in series with it. 
A) zero. 
B) at its maximum value. 
C) equal to the current in a resistive circuit in parallel with the capacitor circuit. 
D) greater than the current in a resistor that is farther from the battery than the capacitor. 
E) zero if it is the only capacitor,but maximum if there is another capacitor in series with it.

Question 6

A capacitor in a single-loop RC circuit is charged to 85% of its final potential difference in 2.4 s.What is the time constant for this circuit?

Accepted Answer

A) 1.5 s 
B) 1.3 s 
C) 1.7 s 
D) 1.9 s 
E) 2.9 s 
A) 1.5 s 
B) 1.3 s 
C) 1.7 s 
D) 1.9 s 
E) 2.9 s

Question 7

A circuit consists of N resistors,all of resistance R,connected as shown below.A potential difference V is applied to the circuit.The equivalent resistance of the circuit is

Accepted Answer

A)    . 
B)    . 
C) R. 
D) NR. 
E) 2NR. 
A)    . 
B)    . 
C) R. 
D) NR. 
E) 2NR.

Question 8

What is the maximum number of 100-W lightbulbs you can connect in parallel in a 120-V home circuit without tripping the 20-A circuit breaker?

Accepted Answer

The answer of What is the maximum number of 100-W...

Question 9

Determine the current in the 10-V emf.

Accepted Answer

A) 2.3 A 
B) 2.7 A 
C) 1.3 A 
D) 0.30 A 
E) 2.5 A 
A) 2.3 A 
B) 2.7 A 
C) 1.3 A 
D) 0.30 A 
E) 2.5 A

Question 10

Determine the magnitude and sense (direction)of the current in the 500-Ω resistor when I = 30 mA.

Accepted Answer

A) 56 mA left to right 
B) 56 mA right to left 
C) 48 mA left to right 
D) 48 mA right to left 
E) 26 mA left to right 
A) 56 mA left to right 
B) 56 mA right to left 
C) 48 mA left to right 
D) 48 mA right to left 
E) 26 mA left to right

Question 11

In an RC circuit,how many time constants must elapse if an initially uncharged capacitor is to reach 80% of its final potential difference?

Accepted Answer

A) 2.2 
B) 1.9 
C) 1.6 
D) 3.0 
E) 5.0 
A) 2.2 
B) 1.9 
C) 1.6 
D) 3.0 
E) 5.0

Question 12

What is the equivalent resistance between points a and b when R = 30 Ω?

Accepted Answer

A) 27 Ω 
B) 21 Ω 
C) 24 Ω 
D) 18 Ω 
E) 7.5 Ω 
A) 27 Ω 
B) 21 Ω 
C) 24 Ω 
D) 18 Ω 
E) 7.5 Ω

Question 13

What is the magnitude of the current in the 20-Ω resistor?

Accepted Answer

A) 0.75 A 
B) 0.00 A 
C) 0.25 A 
D) 0.50 A 
E) 1.00 A 
A) 0.75 A 
B) 0.00 A 
C) 0.25 A 
D) 0.50 A 
E) 1.00 A

Question 14

In a loop in a closed circuit,the sum of the currents entering a junction equals the sum of the currents leaving a junction because

Accepted Answer

A) the potential of the nearest battery is the potential at the junction. 
B) there are no transformations of energy from one type to another in a circuit loop. 
C) capacitors tend to maintain current through them at a constant value. 
D) current is used up after it leaves a junction. 
E) charge is neither created nor destroyed at a junction. 
A) the potential of the nearest battery is the potential at the junction. 
B) there are no transformations of energy from one type to another in a circuit loop. 
C) capacitors tend to maintain current through them at a constant value. 
D) current is used up after it leaves a junction. 
E) charge is neither created nor destroyed at a junction.

Question 15

In an RC circuit,what fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants?

Accepted Answer

A) 0.84 
B) 0.90 
C) 0.75 
D) 0.60 
E) 0.03 
A) 0.84 
B) 0.90 
C) 0.75 
D) 0.60 
E) 0.03

Question 16

The capacitors are completely discharged in the circuit shown below.  
The two resistors have the same resistance R and the two capacitors have the same capacitance C.After the switch is closed,the current

Accepted Answer

A) is greatest in C1. 
B) is greatest in C2. 
C) is greatest in R1. 
D) is greatest in R2. 
E) is the same in C1,C2,R1 and R2. 
A) is greatest in C1. 
B) is greatest in C2. 
C) is greatest in R1. 
D) is greatest in R2. 
E) is the same in C1,C2,R1 and R2.

Question 17

The diagram shown represents a portion of a wire in a circuit.A current is flowing in the wire in the direction shown.Under the convention that it is positive charge that flows the electric field points in the direction of the current.How can the electric field change direction where the wire bends?

Accepted Answer

A) There is an excess of negative charge in the center of the wire. 
B) There is an excess of positive charge at the bottom end of the wire. 
C) There is an excess of negative charge at the right end of the upper portion of the wire. 
D) There is an accumulation of positive charge on the surface,particularly at the bend,such that the sum of electric fields gives the new electric field. 
E) There is an accumulation of electrical potential as the current traverses the wire: The higher potential in the lower half is the source of the field. 
A) There is an excess of negative charge in the center of the wire. 
B) There is an excess of positive charge at the bottom end of the wire. 
C) There is an excess of negative charge at the right end of the upper portion of the wire. 
D) There is an accumulation of positive charge on the surface,particularly at the bend,such that the sum of electric fields gives the new electric field. 
E) There is an accumulation of electrical potential as the current traverses the wire: The higher potential in the lower half is the source of the field.

Question 18

At what rate is thermal energy generated in the 20-Ω resistor when ε = 20 V?

Accepted Answer

A) 6.5 W 
B) 1.6 W 
C) 15 W 
D) 26 W 
E) 5.7 W 
A) 6.5 W 
B) 1.6 W 
C) 15 W 
D) 26 W 
E) 5.7 W

Question 19

If R = 3.0 kΩ,C = 6.0 nF,ε 1 = 10.0 V,Q = 18 nC,ε 2 = 6.0 V,and I = 5.0 mA,what is the potential difference Vb − Va?

Accepted Answer

A) −13 V 
B) +28 V 
C) +13 V 
D) −28 V 
E) +2.0 V 
A) −13 V 
B) +28 V 
C) +13 V 
D) −28 V 
E) +2.0 V

Question 20

If the current in the 4.0-Ω resistor is 1.4 A,what is the magnitude of the potential difference,VA − VB?

Accepted Answer

A) 69 V 
B) 55 V 
C) 62 V 
D) 48 V 
E) 31 V 
A) 69 V 
B) 55 V 
C) 62 V 
D) 48 V 
E) 31 V

Exam 28: Direct-Current Circuits

If I = 2.0 A in the circuit segment shown below,what is the potential difference VB − VA?

At t = 0 the switch S is closed with the capacitor uncharged.If C = 50 μF,ε = 20 V,and R = 4.0 kΩ,what is the charge on the capacitor when I = 2.0 mA?

The circuit below contains three 100-W light bulbs and a capacitor.The emf is 110 V and the capacitor is fully charged.Which light bulb(s)is(are)brightest?

What is the potential difference VB − VA when I = 0.50 A in the circuit segment shown below?

When a capacitor is fully charged,the current through the capacitor in a direct-current circuit is

A capacitor in a single-loop RC circuit is charged to 85% of its final potential difference in 2.4 s.What is the time constant for this circuit?

A circuit consists of N resistors,all of resistance R,connected as shown below.A potential difference V is applied to the circuit.The equivalent resistance of the circuit is

What is the maximum number of 100-W lightbulbs you can connect in parallel in a 120-V home circuit without tripping the 20-A circuit breaker?

Determine the current in the 10-V emf.

Determine the magnitude and sense (direction)of the current in the 500-Ω resistor when I = 30 mA.

In an RC circuit,how many time constants must elapse if an initially uncharged capacitor is to reach 80% of its final potential difference?

What is the equivalent resistance between points a and b when R = 30 Ω?

What is the magnitude of the current in the 20-Ω resistor?

In a loop in a closed circuit,the sum of the currents entering a junction equals the sum of the currents leaving a junction because

In an RC circuit,what fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants?

The capacitors are completely discharged in the circuit shown below. The two resistors have the same resistance R and the two capacitors have the same capacitance C.After the switch is closed,the current

At what rate is thermal energy generated in the 20-Ω resistor when ε = 20 V?

If R = 3.0 kΩ,C = 6.0 nF,ε 1 = 10.0 V,Q = 18 nC,ε 2 = 6.0 V,and I = 5.0 mA,what is the potential difference Vb − Va?

If the current in the 4.0-Ω resistor is 1.4 A,what is the magnitude of the potential difference,VA − VB?

Physics and Measurement

Motion in One Dimension

Vectors

Motion in Two Dimensions

The Laws of Motion

Circular Motion and Other Applications of Newtons Laws

Energy of a System

Conservation of Energy

Linear Momentum and Collisions

Rotation of a Rigid Object About a Fixed Axis

Angular Momentum

Static Equilibrium and Elasticity

Universal Gravitation

Fluid Mechanics

Oscillatory Motion

Wave Motion

Sound Waves

Superposition and Standing Waves

Temperature

The First Law of Thermodynamics

The Kinetic Theory of Gases

Heat Engines, entropy, and the Second Law of Thermodynamics

Electric Fields

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current and Resistance

Magnetic Fields

Sources of the Magnetic Field

Faradays Law

Inductance

Alternating-Current Circuits

Electromagnetic Waves

The Nature of Light and the Principles of Ray Optics

Image Formation

Wave Optics

Diffraction Patterns and Polarization

Relativity

Introduction to Quantum Physics

Quantum Mechanics

Atomic Physics

Molecules and Solids

Nuclear Structure

Applications of Nuclear Physics

Particle Physics and Cosmology

Filters

If I = 2.0 A in the circuit segment shown below,what is the potential difference V_B − V_A?

What is the potential difference V_B − V_A when I = 0.50 A in the circuit segment shown below?

If R = 3.0 kΩ,C = 6.0 nF,ε ₁ = 10.0 V,Q = 18 nC,ε ₂ = 6.0 V,and I = 5.0 mA,what is the potential difference V_b − V_a?

If the current in the 4.0-Ω resistor is 1.4 A,what is the magnitude of the potential difference,V_A − V_B?