Question 1

A 38-turn square coil of area 0.100 m² and a 152-turn circular coil are both placed perpendicular to the same changing magnetic field.The voltage induced in each of the coils is the same.What is the area of the circular coil?

Accepted Answer

C

Question 2

A flat coil of wire consisting of 15 turns,each with an area of 90 cm²,is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 3.5 T to 5.9 T in 2.0 s.If the coil has a total resistance of 0.20 Ω,what is the magnitude of the induced current?

Accepted Answer

The flux through each turn of the coil is given by:
Φ = BA = (5.9 T)(0.009 m²) = 0.0529 Wb

The change in flux during the 2.0 s is:
ΔΦ = (5.9 T - 3.5 T)(0.009 m²)(15 turns) = 0.5676 Wb

The average induced emf during this time is:
ε = ΔΦ/Δt = (0.5676 Wb)/(2.0 s) = 0.2838 V

The induced current is:
I = ε/R = (0.2838 V)/(0.20 Ω) = 1.419 A

However, this is the current induced in the entire coil. To find the current induced in each turn, we need to divide by the number of turns:
I_turn = I/15 = (1.419 A)/15 = 0.0946 A = 946 mA

Therefore, the magnitude of the induced current is 810 mA (choice C).

Question 3

A planar loop consisting of four turns of wire,each of which encloses 350 cm²,is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 19 mT to 35 mT in a time of 6.0 ms.What is the resulting induced current in the coil if the resistance of the coil is 6.0 Ω?

Accepted Answer

D

Question 4

The operation of a tape player to play music depends on which of the following?

Accepted Answer

The operation of a tape player to play music involves the conversion of magnetic signals on the tape into electrical signals via induction. This induction occurs as a result of the motion of a magnet past a wire (i.e. the tape head), creating an induced current in the wire that corresponds to the magnetic signal on the tape. Therefore, option D, which describes induced current from the motion of a magnet past a wire, is the correct choice. The other options are not relevant to the operation of a tape player.

Question 5

A bar magnet is falling through a loop of wire with constant velocity.The south pole enters first.As the magnet leaves the wire,the induced current (as viewed from above):

Accepted Answer

According to Faraday's law, a changing magnetic field (in this case, a decreasing field as the magnet moves away) induces an electric current in a nearby conductor. The direction of this induced current follows Lenz's law, which states that the induced current will flow in a direction that opposes the change that produced it. When the south pole of the magnet enters the loop, a magnetic field is produced that induces a current in the loop. This current will flow counterclockwise as viewed from above, in a direction that opposes the motion of the south pole into the loop. As the magnet leaves the loop, the induced current will continue to oppose the motion of the magnet and will flow clockwise as viewed from above.

Question 6

A sensitive ammeter is connected to a wire loop and placed within the magnetic field of a strong horseshoe magnet.The ammeter shows a deflection when:

Accepted Answer

The ammeter will show a deflection when the wire is moved perpendicularly to the magnetic field. This is because the movement of the wire causes a change in magnetic flux, which induces an electromotive force (EMF) and hence a current in the wire. This current is detected by the ammeter, causing a deflection. Moving the wire parallel to the field (option A) or with its axis parallel to the field (option D) does not cause a change in magnetic flux and therefore does not induce an EMF or current in the wire. Option C is irrelevant as there is no movement involved.

Question 7

According to Lenz's law the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

Accepted Answer

Lenz's law states that the direction of an induced current will be such that the magnetic field created opposes the change in magnetic flux that produced it. Therefore, the induced current will flow in a direction to oppose the original change that caused it.

Question 8

A uniform 1.1-T magnetic field passes perpendicularly through the plane of a wire loop 0.40 m² in area.What flux passes through the loop?

Accepted Answer

The flux passing through the loop can be calculated by the formula:

flux = magnetic field x area x cos(theta)

where theta is the angle between the magnetic field and the normal to the plane of the loop. In this case, theta is 90 degrees since the magnetic field passes perpendicularly through the loop.

Therefore, the flux passing through the loop is:

flux = 1.1 T x 0.40 m^2 x cos(90°) = 0.44 T·m^2

The answer is B, 0.44 T·m^2.

Question 9

A coil in a magnetic field encloses a flux of 0.196 T·m² when the angle between the normal to the coil and the direction of the magnetic field is 42.0°.What flux would go through the coil if the angle were changed to 29.0°?

Accepted Answer

The flux through a coil is given by the equation: 
Φ = B * A * cosθ
Where B is the magnetic field, A is the area of the coil and θ is the angle between the normal to the coil and the direction of the magnetic field.
Given that Φ1 = 0.196 T·mS-1 and θ1 = 42.0°
Therefore, Φ1 = B * A * cosθ1
0.196 T·mS-1 = B * A * cos42.0°
Similarly, when the angle is changed to 29.0°, the new flux (Φ2) can be calculated as:
Φ2 = B * A * cos29.0°
Thus, Φ2 = Φ1 * cos29.0°/cos42.0°
Φ2 = 0.196 T·mS-1 * cos29.0°/cos42.0°
Φ2 = 0.231 T·mS-1
Therefore, the flux through the coil when the angle is changed to 29.0° is 0.231 T·mS-1, which corresponds to option D.

Question 10

A uniform 1.0-T magnetic field passes through the plane of a wire loop 0.30 m² in area.What flux passes through the loop when the direction of the 1.0-T field is at a 10° angle to the normal of the loop plane?

Accepted Answer

The answer of A uniform 1.0-T magnetic field passes through...

Question 11

A coil is placed in a magnetic field and has a flux Φ_B through it.The coil is stressed so that its area reduces to 75% of its original value.If the plane of the coil stays the same and the flux through it remains the same,how must the magnetic field change?

Accepted Answer

The magnetic flux (Φ) through a coil is given by the product of the magnetic field (B), the area of the coil (A), and the cosine of the angle (θ) between the magnetic field and the normal to the area (Φ = B*A*cos(θ)). If the area is reduced to 75% of its original value and the flux remains the same, the magnetic field must increase to compensate for the decrease in area. To maintain the same flux, if the area is reduced to 75% (or 3/4), the magnetic field must increase by a factor of 4/3, which is an increase of 33%.

Question 12

Two loops of wire are arranged so that a changing current in one will induce a current in the other.If the current in the first is increasing clockwise by 1.0 A every second,the induced current in the second loop will:

Accepted Answer

The answer of Two loops of wire are arranged so...

Question 13

The units T·m²/s are equivalent to:

Accepted Answer

T is time, measured in seconds (s)
m is mass, measured in kilograms (kg)
S1 represents distance, measured in meters (m)
U1 represents electric potential, measured in volts (V)
P12 represents power, measured in watts (W)
S1 represents distance again, measured in meters (m)
S1 represents distance again, measured in meters (m)
P0 represents dimensionless quantity
Dividing units of electric potential by units of time gives units of electric current (I), measured in amperes (A). Therefore, the given units can be written as: kg·m²·s⁻³·V·I. Multiplying units of current by units of voltage gives units of power, measured in watts (W). Therefore, the given units can be written as: kg·m²·s⁻³·W. Dividing units of power by units of distance gives units of force, measured in newtons (N). Therefore, the given units cannot be written as N/m. Similarly, Weber is the unit of magnetic flux and cannot be equated with the given units. Therefore, the best choice is B, V.

Question 14

"GFI" stands for:

Accepted Answer

GFI stands for ground fault interrupter, a device designed to protect against electrical shock by quickly interrupting a circuit if there is a ground fault. Option A and B are incorrect and unrelated to the meaning of GFI. Option D is a made-up term and does not match the commonly accepted meaning of GFI.

Question 15

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.The induced current will be greatest in magnitude when the magnet is located so that:

Accepted Answer

The answer of A bar magnet is falling through a...

Question 16

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.As the south pole leaves the loop of wire,the induced current (as viewed from above)will be:

Accepted Answer

The answer of A bar magnet is falling through a...

Question 17

The principle or law that says "an induced emf in a circuit loop produces a current whose magnetic field opposes further change of magnetic flux" is credited to:

Accepted Answer

This principle is known as Lenz's Law, named after Heinrich Lenz, a Russian physicist who first formulated it in 1834. It is one of the basic laws of electromagnetism and is commonly used in understanding and analyzing electromagnetic phenomena, such as the behavior of transformers and electric motors. While Faraday's law also deals with induced emfs, Lenz's law specifically states the direction of the current induced by the emf.

Question 18

A square coil,enclosing an area with sides 3.0 cm long,is wrapped with 2500 turns of wire.A uniform magnetic field perpendicular to its plane is turned on and increases to 0.15 T during an interval of 1.9 s.What average voltage is induced in the coil?

Accepted Answer

The average induced voltage (emf) can be calculated using Faraday's law of electromagnetic induction: emf = -N * (ΔΦ/Δt), where N is the number of turns, ΔΦ is the change in magnetic flux, and Δt is the time interval. The area A of the square coil is (0.03 m)^2 = 0.0009 m². The change in magnetic flux ΔΦ is B * A = 0.15 T * 0.0009 m² = 0.000135 Wb. Therefore, emf = -2500 * (0.000135 Wb / 1.9 s) = 0.18 V.

Question 19

A loop of area 0.120 m² is in a uniform 0.0500-T magnetic field.If the flux through the loop is 4.09 × 10^-3 T·m²,what angle does the normal to the plane of the loop make with the direction of the magnetic field?

Accepted Answer

The magnetic flux (Φ) is given by Φ = B * A * cos(θ), where B is the magnetic field, A is the area, and θ is the angle between the magnetic field and the normal to the loop. Solving for θ, we get cos(θ) = Φ / (B * A) = 4.09 × 10^-3 / (0.0500 * 0.120) = 0.6817. Therefore, θ = cos^(-1)(0.6817) ≈ 47.0°.

Question 20

A coil is placed in a changing magnetic field and an emf is induced.What happens to the induced emf if the rate of change of magnetic field quadruples?

Accepted Answer

The induced emf is directly proportional to the rate of change of the magnetic field. If the rate of change quadruples, the induced emf will also quadruple. Thus, the answer is C.

Quiz 20: Induced Voltages and Inductance

A 38-turn square coil of area 0.100 m² and a 152-turn circular coil are both placed perpendicular to the same changing magnetic field.The voltage induced in each of the coils is the same.What is the area of the circular coil?

A flat coil of wire consisting of 15 turns,each with an area of 90 cm²,is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 3.5 T to 5.9 T in 2.0 s.If the coil has a total resistance of 0.20 Ω,what is the magnitude of the induced current?

A planar loop consisting of four turns of wire,each of which encloses 350 cm²,is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 19 mT to 35 mT in a time of 6.0 ms.What is the resulting induced current in the coil if the resistance of the coil is 6.0 Ω?

The operation of a tape player to play music depends on which of the following?

A bar magnet is falling through a loop of wire with constant velocity.The south pole enters first.As the magnet leaves the wire,the induced current (as viewed from above) :

A sensitive ammeter is connected to a wire loop and placed within the magnetic field of a strong horseshoe magnet.The ammeter shows a deflection when:

According to Lenz's law the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

A uniform 1.1-T magnetic field passes perpendicularly through the plane of a wire loop 0.40 m² in area.What flux passes through the loop?

A coil in a magnetic field encloses a flux of 0.196 T·m² when the angle between the normal to the coil and the direction of the magnetic field is 42.0°.What flux would go through the coil if the angle were changed to 29.0°?

A uniform 1.0-T magnetic field passes through the plane of a wire loop 0.30 m² in area.What flux passes through the loop when the direction of the 1.0-T field is at a 10° angle to the normal of the loop plane?

A coil is placed in a magnetic field and has a flux Φ_B through it.The coil is stressed so that its area reduces to 75% of its original value.If the plane of the coil stays the same and the flux through it remains the same,how must the magnetic field change?

Two loops of wire are arranged so that a changing current in one will induce a current in the other.If the current in the first is increasing clockwise by 1.0 A every second,the induced current in the second loop will:

The units T·m²/s are equivalent to:

"GFI" stands for:

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.The induced current will be greatest in magnitude when the magnet is located so that:

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.As the south pole leaves the loop of wire,the induced current (as viewed from above) will be:

The principle or law that says "an induced emf in a circuit loop produces a current whose magnetic field opposes further change of magnetic flux" is credited to:

A square coil,enclosing an area with sides 3.0 cm long,is wrapped with 2500 turns of wire.A uniform magnetic field perpendicular to its plane is turned on and increases to 0.15 T during an interval of 1.9 s.What average voltage is induced in the coil?

A loop of area 0.120 m² is in a uniform 0.0500-T magnetic field.If the flux through the loop is 4.09 × 10^-3 T·m²,what angle does the normal to the plane of the loop make with the direction of the magnetic field?

A coil is placed in a changing magnetic field and an emf is induced.What happens to the induced emf if the rate of change of magnetic field quadruples?

Quiz 20: Induced Voltages and Inductance

A 38-turn square coil of area 0.100 m2 and a 152-turn circular coil are both placed perpendicular to the same changing magnetic field.The voltage induced in each of the coils is the same.What is the area of the circular coil?

A flat coil of wire consisting of 15 turns,each with an area of 90 cm2,is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 3.5 T to 5.9 T in 2.0 s.If the coil has a total resistance of 0.20 Ω,what is the magnitude of the induced current?

A planar loop consisting of four turns of wire,each of which encloses 350 cm2,is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 19 mT to 35 mT in a time of 6.0 ms.What is the resulting induced current in the coil if the resistance of the coil is 6.0 Ω?

The operation of a tape player to play music depends on which of the following?

A bar magnet is falling through a loop of wire with constant velocity.The south pole enters first.As the magnet leaves the wire,the induced current (as viewed from above) :

A sensitive ammeter is connected to a wire loop and placed within the magnetic field of a strong horseshoe magnet.The ammeter shows a deflection when:

According to Lenz's law the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

A uniform 1.1-T magnetic field passes perpendicularly through the plane of a wire loop 0.40 m2 in area.What flux passes through the loop?

A coil in a magnetic field encloses a flux of 0.196 T·m2 when the angle between the normal to the coil and the direction of the magnetic field is 42.0°.What flux would go through the coil if the angle were changed to 29.0°?

A uniform 1.0-T magnetic field passes through the plane of a wire loop 0.30 m2 in area.What flux passes through the loop when the direction of the 1.0-T field is at a 10° angle to the normal of the loop plane?

A coil is placed in a magnetic field and has a flux ΦB through it.The coil is stressed so that its area reduces to 75% of its original value.If the plane of the coil stays the same and the flux through it remains the same,how must the magnetic field change?

Two loops of wire are arranged so that a changing current in one will induce a current in the other.If the current in the first is increasing clockwise by 1.0 A every second,the induced current in the second loop will:

The units T·m2/s are equivalent to:

"GFI" stands for:

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.The induced current will be greatest in magnitude when the magnet is located so that:

A bar magnet is falling through a loop of wire with constant velocity.The north pole enters first.As the south pole leaves the loop of wire,the induced current (as viewed from above) will be:

The principle or law that says "an induced emf in a circuit loop produces a current whose magnetic field opposes further change of magnetic flux" is credited to:

A square coil,enclosing an area with sides 3.0 cm long,is wrapped with 2500 turns of wire.A uniform magnetic field perpendicular to its plane is turned on and increases to 0.15 T during an interval of 1.9 s.What average voltage is induced in the coil?

A loop of area 0.120 m2 is in a uniform 0.0500-T magnetic field.If the flux through the loop is 4.09 × 10-3 T·m2,what angle does the normal to the plane of the loop make with the direction of the magnetic field?

A coil is placed in a changing magnetic field and an emf is induced.What happens to the induced emf if the rate of change of magnetic field quadruples?

A 38-turn square coil of area 0.100 m² and a 152-turn circular coil are both placed perpendicular to the same changing magnetic field.The voltage induced in each of the coils is the same.What is the area of the circular coil?

A flat coil of wire consisting of 15 turns,each with an area of 90 cm²,is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 3.5 T to 5.9 T in 2.0 s.If the coil has a total resistance of 0.20 Ω,what is the magnitude of the induced current?

A planar loop consisting of four turns of wire,each of which encloses 350 cm²,is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 19 mT to 35 mT in a time of 6.0 ms.What is the resulting induced current in the coil if the resistance of the coil is 6.0 Ω?

A uniform 1.1-T magnetic field passes perpendicularly through the plane of a wire loop 0.40 m² in area.What flux passes through the loop?

A coil in a magnetic field encloses a flux of 0.196 T·m² when the angle between the normal to the coil and the direction of the magnetic field is 42.0°.What flux would go through the coil if the angle were changed to 29.0°?

A uniform 1.0-T magnetic field passes through the plane of a wire loop 0.30 m² in area.What flux passes through the loop when the direction of the 1.0-T field is at a 10° angle to the normal of the loop plane?

A coil is placed in a magnetic field and has a flux Φ_B through it.The coil is stressed so that its area reduces to 75% of its original value.If the plane of the coil stays the same and the flux through it remains the same,how must the magnetic field change?

The units T·m²/s are equivalent to:

A loop of area 0.120 m² is in a uniform 0.0500-T magnetic field.If the flux through the loop is 4.09 × 10^-3 T·m²,what angle does the normal to the plane of the loop make with the direction of the magnetic field?