Question 1

A long solenoid has a radius of 4.0 cm and has 800 turns/m.If the current in the solenoid is increasing at the rate of 3.0 A/s, what is the magnitude of the induced electric field at a point 2.2 cm from the axis of the solenoid?

Accepted Answer

The induced electric field inside a solenoid is given by E = (μ₀ * n * r * (dI/dt)) / 2, where μ₀ is the permeability of free space, n is the number of turns per unit length, r is the distance from the axis, and dI/dt is the rate of change of current. Substituting the given values, E = (4π * 10^-7 T*m/A * 800 turns/m * 0.022 m * 3 A/s) / 2 = 3.3 * 10^-5 V/m.

Question 2

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is open:

Accepted Answer

The answer of Two bulbs are shown in a circuit...

Question 3

An electric field of 4.0 $\mu$V/m is induced at a point 2.0 cm from the axis of a long solenoid (radius = 3.0 cm, 800 turns/m).At what rate is the current in the solenoid changing at this instant?

Accepted Answer

The answer of An electric field of 4.0 $\mu$V/m is...

Question 4

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates clockwise about an axis through its centre at constant angular velocity  $ \omega $.While it rotates, the point(s) at lowest potential is(are):

Accepted Answer

The answer of A metal rod of length L in...

Question 5

A long solenoid (radius = 3.0 cm, 2500 turns per metre) carries a current given by I = 0.30 sin(200 $\pi$t) A, where t is measured in s.When t = 5.0 ms, what is the magnitude of the induced electric field at a point which is 2.0 cm from the axis of the solenoid?

Accepted Answer

The answer of A long solenoid (radius = 3.0 cm,...

Question 6

As shown below, a square loop of wire of side a moves through a uniform magnetic field of magnitude B perpendicular to the page at constant velocity directed to the right.Judd says that the emf induced in the loop is zero.Roger claims that it has magnitude B.Which one, if either, is correct, and why?

Accepted Answer

The answer of As shown below, a square loop of...

Question 7

A long solenoid has a radius of 2.0 cm and has 700 turns/m.If the current in the solenoid is decreasing at the rate of 8.0 A/s, what is the magnitude of the induced electric field at a point 2.5 cm from the axis of the solenoid?

Accepted Answer

The answer of A long solenoid has a radius of...

Question 8

The magnetic flux through a loop perpendicular to a uniform magnetic field will change:

Accepted Answer

Rotating the loop through 180 degrees changes the direction of the magnetic field relative to the loop, thus changing the magnetic flux.

Question 9

A current may be induced in a coil by:

Accepted Answer

All of the given options are correct ways to induce a current in a coil. Moving a magnetic field through a coil or moving a coil through a magnetic field will induce a current. Additionally, if a changing current is flowing through a nearby coil, it will create a changing magnetic field which in turn can induce a current in the first coil.

Question 10

A conducting bar of length L rotates with a constant angular speed of +2.0 rad/s about a pivot P at one end, as shown.A uniform magnetic field (magnitude = 0.20 T) is directed into the paper.If L = 0.40 m, what is the potential difference, VA - VP?

Accepted Answer

We can use the formula for the induced EMF in a rotating conductor in a magnetic field:

EMF = B*L^2*w/2

where B is the magnetic field, L is the length of the conductor, and w is the angular velocity.

Substituting the given values, we get:

EMF = (0.20 T)*(0.40 m)^2*(2.0 rad/s)/2 = 0.016 V = 16 mV

However, we need to consider the direction of the induced EMF. By the right-hand rule, the direction of the induced current will be such that it opposes the change in magnetic flux. In this case, as the bar rotates, the area of the loop enclosed by the bar and the magnetic field decreases, so the induced current will create a magnetic field in the opposite direction to the external magnetic field. This means that the potential difference across the length of the bar will be from the end closest to the pivot point (which we will call point A) to the other end (which we will call point B).

Therefore, the potential difference VA - VB is given by:

VA - VB = EMF = 16 mV

But we need to find VA - VP, not VA - VB. Since the bar is rotating with a constant angular velocity, there is no potential difference between points B and P (since they are both at the same distance from the pivot point and are moving at the same speed). So we have:

VA - VP = VA - VB = 16 mV

Therefore, the answer is choice C: (F1F1F1S1F1F1F108.0 mV).

Question 11

An induced emf is produced in:

Accepted Answer

An induced emf is produced in a closed loop of wire moving at constant velocity in a nonuniform static magnetic field due to the change in magnetic flux through the loop, as per Faraday's law of electromagnetic induction.

Question 12

A bar (L = 80 cm) moves on two frictionless rails, as shown, in a region where the magnetic field is uniform (B = 0.30 T) and into the paper.If v = 50 cm/s and R = 60 m $\Omega$ , what is the magnetic force on the moving bar?

Accepted Answer

The answer of A bar (L = 80 cm) moves...

Question 13

An AC generator consists of 6 turns of wire.Each turn has an area of 0.040 m2.The loop rotates in a uniform field (B = 0.20 T) at a constant frequency of 50 Hz.What is the maximum induced emf?

Accepted Answer

The maximum induced EMF can be calculated using the formula:
EMF = NABωsin(ωt)
where N is the number of turns, A is the area of each turn, B is the magnetic field, ω is the angular frequency, and t is the time.

Substituting the given values, we get:
EMF = 6 x 0.040 x 0.20 x 2π x 50 x sin(2πft)
EMF = 15.1 V

Therefore, the maximum induced EMF is 15 V, which is closest to option D.

Question 14

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

Accepted Answer

The answer of Two bulbs are shown in a circuit...

Question 15

At what frequency should a 200-turn, flat coil of cross sectional area of 300 cm2 be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V?

Accepted Answer

The answer of At what frequency should a 200-turn, flat...

Question 16

The difference between a DC and an AC generator is that:

Accepted Answer

A DC generator has one slip ring split in two halves to provide a means of connecting the outer ends of the armature windings to an external circuit. An AC generator, on the other hand, has two slip rings, one for each end of the armature windings. Therefore, options A, B, D, and E are incorrect.

Question 17

Coil 1, connected to a 100$\Omega$resistor, sits inside coil 2.Coil 1 is connected to a source of 60 cycle per second AC current.Which statement about coil 2 is correct?

Accepted Answer

When a varying current is passed through a coil, it produces a varying magnetic field around it. This varying magnetic field will induce an EMF in a nearby coil, as per Faraday's law of electromagnetic induction. As the current in coil 1 is AC, its magnetic field will also keep changing in direction and magnitude at 60 cycles per second. This will induce an AC current in coil 2 as well. Therefore, option C is correct.

Question 18

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

Accepted Answer

The answer of Two bulbs are shown in a circuit...

Question 19

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates clockwise about an axis through its centre at constant angular velocity  $ \omega $.While it rotates, the point(s) at highest potential is(are):

Accepted Answer

The answer of A metal rod of length L in...

Question 20

A bar magnet is dropped from above and falls through the loop of wire shown below.The north pole of the bar magnet points downward towards the page as it falls.Which statement is correct?

Accepted Answer

As the north pole of the bar magnet falls through the loop, a clockwise current is induced in the loop, according to Lenz's law. When the magnet reaches the center of the loop, the magnetic field around it starts to decrease, and so the induced current reverses direction and flows counter clockwise. Therefore, the current flows first in a counter clockwise direction, then in a clockwise direction, making option D the correct answer.

Quiz 9: Faradays Law

A long solenoid has a radius of 4.0 cm and has 800 turns/m.If the current in the solenoid is increasing at the rate of 3.0 A/s, what is the magnitude of the induced electric field at a point 2.2 cm from the axis of the solenoid?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is open:

An electric field of 4.0 $\mu$ V/m is induced at a point 2.0 cm from the axis of a long solenoid (radius = 3.0 cm, 800 turns/m) .At what rate is the current in the solenoid changing at this instant?

A long solenoid (radius = 3.0 cm, 2500 turns per metre) carries a current given by I = 0.30 sin(200 $\pi$ t) A, where t is measured in s.When t = 5.0 ms, what is the magnitude of the induced electric field at a point which is 2.0 cm from the axis of the solenoid?

A long solenoid has a radius of 2.0 cm and has 700 turns/m.If the current in the solenoid is decreasing at the rate of 8.0 A/s, what is the magnitude of the induced electric field at a point 2.5 cm from the axis of the solenoid?

The magnetic flux through a loop perpendicular to a uniform magnetic field will change:

A current may be induced in a coil by:

A conducting bar of length L rotates with a constant angular speed of +2.0 rad/s about a pivot P at one end, as shown.A uniform magnetic field (magnitude = 0.20 T) is directed into the paper.If L = 0.40 m, what is the potential difference, VA - VP?

An induced emf is produced in:

An AC generator consists of 6 turns of wire.Each turn has an area of 0.040 m2.The loop rotates in a uniform field (B = 0.20 T) at a constant frequency of 50 Hz.What is the maximum induced emf?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

At what frequency should a 200-turn, flat coil of cross sectional area of 300 cm2 be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V?

The difference between a DC and an AC generator is that:

Coil 1, connected to a 100 $\Omega$ resistor, sits inside coil 2.Coil 1 is connected to a source of 60 cycle per second AC current.Which statement about coil 2 is correct?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

A bar magnet is dropped from above and falls through the loop of wire shown below.The north pole of the bar magnet points downward towards the page as it falls.Which statement is correct?

Quiz 9: Faradays Law

A long solenoid has a radius of 4.0 cm and has 800 turns/m.If the current in the solenoid is increasing at the rate of 3.0 A/s, what is the magnitude of the induced electric field at a point 2.2 cm from the axis of the solenoid?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is open:

An electric field of 4.0 μ\muμ V/m is induced at a point 2.0 cm from the axis of a long solenoid (radius = 3.0 cm, 800 turns/m) .At what rate is the current in the solenoid changing at this instant?

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates clockwise about an axis through its centre at constant angular velocity ω \omega ω .While it rotates, the point(s) at lowest potential is(are) :

A long solenoid (radius = 3.0 cm, 2500 turns per metre) carries a current given by I = 0.30 sin(200 π\piπ t) A, where t is measured in s.When t = 5.0 ms, what is the magnitude of the induced electric field at a point which is 2.0 cm from the axis of the solenoid?

A long solenoid has a radius of 2.0 cm and has 700 turns/m.If the current in the solenoid is decreasing at the rate of 8.0 A/s, what is the magnitude of the induced electric field at a point 2.5 cm from the axis of the solenoid?

The magnetic flux through a loop perpendicular to a uniform magnetic field will change:

A current may be induced in a coil by:

A conducting bar of length L rotates with a constant angular speed of +2.0 rad/s about a pivot P at one end, as shown.A uniform magnetic field (magnitude = 0.20 T) is directed into the paper.If L = 0.40 m, what is the potential difference, VA - VP?

An induced emf is produced in:

A bar (L = 80 cm) moves on two frictionless rails, as shown, in a region where the magnetic field is uniform (B = 0.30 T) and into the paper.If v = 50 cm/s and R = 60 m Ω\OmegaΩ , what is the magnetic force on the moving bar?

An AC generator consists of 6 turns of wire.Each turn has an area of 0.040 m2.The loop rotates in a uniform field (B = 0.20 T) at a constant frequency of 50 Hz.What is the maximum induced emf?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

At what frequency should a 200-turn, flat coil of cross sectional area of 300 cm2 be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V?

The difference between a DC and an AC generator is that:

Coil 1, connected to a 100 Ω\OmegaΩ resistor, sits inside coil 2.Coil 1 is connected to a source of 60 cycle per second AC current.Which statement about coil 2 is correct?

Two bulbs are shown in a circuit that surrounds a region of increasing magnetic field directed out of the page.When the switch is closed:

A metal rod of length L in a region of space where a constant magnetic field points into the page rotates clockwise about an axis through its centre at constant angular velocity ω \omega ω .While it rotates, the point(s) at highest potential is(are) :

A bar magnet is dropped from above and falls through the loop of wire shown below.The north pole of the bar magnet points downward towards the page as it falls.Which statement is correct?

An electric field of 4.0 $\mu$ V/m is induced at a point 2.0 cm from the axis of a long solenoid (radius = 3.0 cm, 800 turns/m) .At what rate is the current in the solenoid changing at this instant?

A long solenoid (radius = 3.0 cm, 2500 turns per metre) carries a current given by I = 0.30 sin(200 $\pi$ t) A, where t is measured in s.When t = 5.0 ms, what is the magnitude of the induced electric field at a point which is 2.0 cm from the axis of the solenoid?

Coil 1, connected to a 100 $\Omega$ resistor, sits inside coil 2.Coil 1 is connected to a source of 60 cycle per second AC current.Which statement about coil 2 is correct?