Question 1

A coil with a self-inductance of 6.0 H has a constant current of 2.0 A flowing through it for 2.0 s.What is the emf induced in this coil?

Accepted Answer

A) 6.0 V 
B) 12 V 
C) 0.0 V 
D) 4.0 V 
E) 8.0 V 
A) 6.0 V 
B) 12 V 
C) 0.0 V 
D) 4.0 V 
E) 8.0 V

Question 2

A bar magnet is oriented above a copper ring,as shown in the figure.If the magnet is kept fixed while the ring is dropped,what is the direction of the current induced in the ring,as viewed from below the ring?

Accepted Answer

A) There is no current in the ring. 
B) counterclockwise 
C) clockwise 
A) There is no current in the ring. 
B) counterclockwise 
C) clockwise

Question 3

A constant uniform magnetic field of 0.50 T is applied at right angles to the plane of a flat rectangular loop of area 3.0 ×  
 
.If the area of this loop changes steadily from its original value to a new value of 1.6 × 10-3 m2 in 1.6 s,what is the emf induced in the loop?

Accepted Answer

A) 1.6 ×   V 
B) 0 V 
C) 7.5 ×   V 
D) 4.4 ×   V 
E) 9.0 ×   V 
A) 1.6 ×   V 
B) 0 V 
C) 7.5 ×   V 
D) 4.4 ×   V 
E) 9.0 ×   V

Question 4

A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T.Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are parallel.

Accepted Answer

A) 0 T ∙ m2 
B) 3.1 × 10-3 T ∙ m2 
C) 5.5 × 10-3 T ∙ m2 
D) 6.3 × 10-3 T ∙ m2 
A) 0 T ∙ m2 
B) 3.1 × 10-3 T ∙ m2 
C) 5.5 × 10-3 T ∙ m2 
D) 6.3 × 10-3 T ∙ m2

Question 5

The inductance of a solenoid that is 16.0 cm long and has a cross-sectional area of 1.00 ×  
 
Is  
How many turns of wire does this solenoid have? (μ0 = 4π × 10-7 T ∙ m/A)

Accepted Answer

A) 318,000 
B) 159,000 
C) 1130 
D) 282 
E) 150 
A) 318,000 
B) 159,000 
C) 1130 
D) 282 
E) 150

Question 6

A resistor and an inductor are connected in series to a battery.The time constant for the circuit represents the time required for the current to reach

Accepted Answer

A) 25% of the maximum current. 
B) 37% of the maximum current. 
C) 63% of the maximum current. 
D) 75% of the maximum current. 
E) 100% of the maximum current. 
A) 25% of the maximum current. 
B) 37% of the maximum current. 
C) 63% of the maximum current. 
D) 75% of the maximum current. 
E) 100% of the maximum current.

Question 7

An ideal transformer consists of a 500-turn primary coil and a 2000-turn secondary coil.If the current in the secondary is 3.0 A,what is the current in the primary?

Accepted Answer

A) 0.75 A 
B) 1.3 A 
C) 12 A 
D) 48 A 
A) 0.75 A 
B) 1.3 A 
C) 12 A 
D) 48 A

Question 8

The primary of an ideal transformer has 100 turns and its secondary has 200 turns.If the input current at the primary is 100 A,we can expect the output current at the secondary to be

Accepted Answer

A) 50 A. 
B) 100 A. 
C) 200 A. 
D) none of the given answers. 
A) 50 A. 
B) 100 A. 
C) 200 A. 
D) none of the given answers.

Question 9

An electromagnetic flowmeter is useful when it is desirable not to interrupt the system in which the fluid is flowing (such as the blood in an artery during heart surgery).Such a device is illustrated in the figure.The conducting fluid moves with speed v in a tube of diameter d.Perpendicular to this tube is a magnetic field B.A voltage V is induced between opposite sides of the tube due to the motion of the conducting fluid in the magnetic field.For a certain case,B = 0.120 T,d = 1.2 cm,and the measured voltage is  
Determine the speed of the fluid.

Accepted Answer

A) 2.0 m/s 
B) 11 m/s 
C) 0.075 m/s 
D) 1.1 m/s 
E) 750 m/s 
A) 2.0 m/s 
B) 11 m/s 
C) 0.075 m/s 
D) 1.1 m/s 
E) 750 m/s

Question 10

An ideal solenoid with 3000 turns is 70.0 cm long.If its self-inductance is 25.0 mH,what is its radius? (μ0 = 4π × 10-7 T ∙ m/A)

Accepted Answer

A) 0.0222 m 
B) 0.00199 m 
C) 327 m 
D) 52.0 m 
A) 0.0222 m 
B) 0.00199 m 
C) 327 m 
D) 52.0 m

Question 11

A bar magnet is oriented above a copper ring,as shown in the figure.The magnet is dropped and passes completely through the ring.As viewed from above,what is the direction of the current induced in the ring after the magnet has completely passed through the ring and is somewhat below it?

Accepted Answer

A) There is no current in the ring. 
B) counterclockwise 
C) clockwise 
A) There is no current in the ring. 
B) counterclockwise 
C) clockwise

Question 12

A coil of wire containing N turns is in an external magnetic field that is perpendicular to the plane of the coil and it steadily changing.Under these circumstances,an emf ε is induced in the coil.If the rate of change of the magnetic field and the number of turns in the coil are now doubled (but nothing else changes),what will be the induced emf in the coil?

Accepted Answer

A) 2ε 
B) ε/2 
C) 4ε 
D) ε/4 
E) ε 
A) 2ε 
B) ε/2 
C) 4ε 
D) ε/4 
E) ε

Question 13

A round flat conducting loop is placed perpendicular to a uniform 0.50 T magnetic field.If the area of the loop increases at a rate of 3.0 ×  
 
/s,what is the induced emf in the loop?

Accepted Answer

A) 4.3 mV 
B) 0 mV 
C) 1.5 mV 
D) 1.7 mV 
E) 5.5 mV 
A) 4.3 mV 
B) 0 mV 
C) 1.5 mV 
D) 1.7 mV 
E) 5.5 mV

Question 14

As shown in the figure,a battery supplies a steady current to the solenoid on the left.The two solenoids are moving toward each other with speeds v.The direction of the induced current through the resistor R is

Accepted Answer

A) from a to b. 
B) from b to a. 
C) No current is induced. 
A) from a to b. 
B) from b to a. 
C) No current is induced.

Question 15

The magnetic flux through a coil changes steadily from 4.0 × 10-5 T ∙ m2 to 5.0 × 10-5 T ∙ m2 in 0.10 s.What emf is induced in this coil?

Accepted Answer

A) 5.0 × 10-4 V 
B) 4.0 × 10-4 V 
C) 1.0 × 10-4 V 
D) None of the given answers are correct. 
A) 5.0 × 10-4 V 
B) 4.0 × 10-4 V 
C) 1.0 × 10-4 V 
D) None of the given answers are correct.

Question 16

A current of 2.0 A in the 100-turn primary of an ideal transformer causes 14 A to flow in the secondary.How many turns are in the secondary?

Accepted Answer

A) 700 
B) 114 
C) 14 
D) 4 
A) 700 
B) 114 
C) 14 
D) 4

Question 17

The primary of an ideal transformer has 100 turns and its secondary has 200 turns.Neglecting frictional losses,if the power input to the primary is 100 W,we can expect the power output of the secondary to be

Accepted Answer

A) 50 W. 
B) 100 W. 
C) 200 W. 
D) none of the given answers. 
A) 50 W. 
B) 100 W. 
C) 200 W. 
D) none of the given answers.

Question 18

Two solenoids are close to each other,as shown in the figure,with the switch S open.When the switch is suddenly closed,which way will the induced current flow through the galvanometer in the left-hand solenoid?

Accepted Answer

A) from left to right 
B) from right to left 
C) There will be no induced current through the galvanometer. 
A) from left to right 
B) from right to left 
C) There will be no induced current through the galvanometer.

Question 19

A long straight wire lies on a horizontal table and carries an ever-increasing current toward the north.Two coils of wire lie flat on the table,one on either side of the wire.When viewed from above,the direction of the induced current in these coils is

Accepted Answer

A) clockwise in both coils. 
B) counterclockwise in both coils. 
C) clockwise in the east coil and counterclockwise in the west coil. 
D) counterclockwise in the east coil and clockwise in the west coil. 
A) clockwise in both coils. 
B) counterclockwise in both coils. 
C) clockwise in the east coil and counterclockwise in the west coil. 
D) counterclockwise in the east coil and clockwise in the west coil.

Question 20

At a certain instant,coil A is in a 10-T external magnetic field and coil B is in a 1-T external magnetic field.Both coils have the same area and are oriented at right angles to the field.Which coil will have a greater emf induced in it?

Accepted Answer

A) coil A 
B) coil B 
C) It is impossible to know without more information about the fields. 
A) coil A 
B) coil B 
C) It is impossible to know without more information about the fields.

Exam 23: Magnetic Flux and Faradays Law of Induction

A coil with a self-inductance of 6.0 H has a constant current of 2.0 A flowing through it for 2.0 s.What is the emf induced in this coil?

A bar magnet is oriented above a copper ring,as shown in the figure.If the magnet is kept fixed while the ring is dropped,what is the direction of the current induced in the ring,as viewed from below the ring?

A constant uniform magnetic field of 0.50 T is applied at right angles to the plane of a flat rectangular loop of area 3.0 × .If the area of this loop changes steadily from its original value to a new value of 1.6 × 10-3 m2 in 1.6 s,what is the emf induced in the loop?

A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T.Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are parallel.

The inductance of a solenoid that is 16.0 cm long and has a cross-sectional area of 1.00 × Is How many turns of wire does this solenoid have? (μ0 = 4π × 10-7 T ∙ m/A)

A resistor and an inductor are connected in series to a battery.The time constant for the circuit represents the time required for the current to reach

An ideal transformer consists of a 500-turn primary coil and a 2000-turn secondary coil.If the current in the secondary is 3.0 A,what is the current in the primary?

The primary of an ideal transformer has 100 turns and its secondary has 200 turns.If the input current at the primary is 100 A,we can expect the output current at the secondary to be

An ideal solenoid with 3000 turns is 70.0 cm long.If its self-inductance is 25.0 mH,what is its radius? (μ0 = 4π × 10-7 T ∙ m/A)

A bar magnet is oriented above a copper ring,as shown in the figure.The magnet is dropped and passes completely through the ring.As viewed from above,what is the direction of the current induced in the ring after the magnet has completely passed through the ring and is somewhat below it?

A round flat conducting loop is placed perpendicular to a uniform 0.50 T magnetic field.If the area of the loop increases at a rate of 3.0 × /s,what is the induced emf in the loop?

As shown in the figure,a battery supplies a steady current to the solenoid on the left.The two solenoids are moving toward each other with speeds v.The direction of the induced current through the resistor R is

The magnetic flux through a coil changes steadily from 4.0 × 10-5 T ∙ m2 to 5.0 × 10-5 T ∙ m2 in 0.10 s.What emf is induced in this coil?

A current of 2.0 A in the 100-turn primary of an ideal transformer causes 14 A to flow in the secondary.How many turns are in the secondary?

The primary of an ideal transformer has 100 turns and its secondary has 200 turns.Neglecting frictional losses,if the power input to the primary is 100 W,we can expect the power output of the secondary to be

Two solenoids are close to each other,as shown in the figure,with the switch S open.When the switch is suddenly closed,which way will the induced current flow through the galvanometer in the left-hand solenoid?

A long straight wire lies on a horizontal table and carries an ever-increasing current toward the north.Two coils of wire lie flat on the table,one on either side of the wire.When viewed from above,the direction of the induced current in these coils is

At a certain instant,coil A is in a 10-T external magnetic field and coil B is in a 1-T external magnetic field.Both coils have the same area and are oriented at right angles to the field.Which coil will have a greater emf induced in it?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Electric Current and Direct-Current Circuits

Magnetism

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters

A constant uniform magnetic field of 0.50 T is applied at right angles to the plane of a flat rectangular loop of area 3.0 × .If the area of this loop changes steadily from its original value to a new value of 1.6 × 10^-3 m² in 1.6 s,what is the emf induced in the loop?

The inductance of a solenoid that is 16.0 cm long and has a cross-sectional area of 1.00 × Is How many turns of wire does this solenoid have? (μ₀ = 4π × 10^-7 T ∙ m/A)

An ideal solenoid with 3000 turns is 70.0 cm long.If its self-inductance is 25.0 mH,what is its radius? (μ₀ = 4π × 10^-7 T ∙ m/A)

The magnetic flux through a coil changes steadily from 4.0 × 10^-5 T ∙ m² to 5.0 × 10^-5 T ∙ m² in 0.10 s.What emf is induced in this coil?