$$4\pi \times 10$$^{-7}$$ T\cdot m/A

Question 1

Which equation correctly describes the torque $$	au$$ experienced by a current-carrying coil in a uniform magnetic field?

Accepted Answer

$$	au = NIA \sin \phi$$

Question 2

A solenoid is defined as:

Accepted Answer

A long coil of wire in the shape of a helix

Question 3

What is the direction of the magnetic field produced by a current-carrying straight wire, as determined by the Right Hand Rule?

Accepted Answer

Perpendicular to the wire, forming concentric circles around it

Question 4

For a loop of wire carrying current, what is the direction of the magnetic field at the center of the loop?

Accepted Answer

Perpendicular to the plane of the loop

Question 5

Which formula gives the magnetic field $$B at $$the center of a circular loop of radius $$R$$ carrying current $$I$$ with $$N$$ turns?

Accepted Answer

$$B = \frac{\mu_0$ N I}{2 R}$$

Question 6

What happens to the net force on a current-carrying wire loop placed in a uniform magnetic field?

Accepted Answer

The net force is zero, but a torque is produced

Question 7

The maximum torque on a current-carrying coil occurs when:

Accepted Answer

The normal to the coil is perpendicular to the magnetic field

Question 8

Which of the following best describes the magnetic moment of a coil?

Accepted Answer

It is proportional to the current and the area of the coil

Question 9

For a solenoid, the magnetic field inside is given by:

Accepted Answer

$$B = \mu_0$ n I$$

Question 10

If two parallel wires carry currents in the same direction, what is the nature of the force between them?

Accepted Answer

They attract each other

Question 11

Which of the following is NOT a real-world application of electric motors based on current-carrying coils?

Accepted Answer

Solar panels

Question 12

The permeability of free space $$\mu_0$ is:

Accepted Answer

$$4\pi 	imes 10$$^{-7}$$ T\cdot m/A

Question 13

What is the magnetic flux $$\Phi$$ through a loop of area $$A in a $$magnetic field $$B at an $$angle $$Z to $$the normal?

Accepted Answer

$$\Phi = BA \cos Z$$

Question 14

Which statement about the magnetic field outside a solenoid is correct?

Accepted Answer

It is much weaker and varies with position

Question 15

In electromagnetic wave propagation, the electric and magnetic fields:

Accepted Answer

Oscillate 90 degrees out of phase with each other

Question 16

A wire loop carrying current acts like a magnet because:

Accepted Answer

It produces a magnetic field with a north and south pole

Question 17

If the current in a solenoid is doubled, what happens to the magnetic field inside?

Accepted Answer

It is doubled

Question 18

Which of the following best describes the effect of increasing the number of turns per unit length in a solenoid?

Accepted Answer

The magnetic field inside increases

Question 19

A current-carrying wire loop placed in a uniform magnetic field will:

Accepted Answer

Experience a torque causing rotation

Question 20

Which equation gives the magnetic field $$B at a $$distance $$r$$ from an infinitely long straight wire carrying current $$I$$?

Accepted Answer

$$B = \frac{\mu_0$ I}{2 \pi r}$$

Chapter 27 Part II - Current,Carrying Coils, Magnetic Fields, and Resulting Torque

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