Question 1

When a switch is closed allowing current to flow in coil A, the current induced in a nearby coaxial but unconnected coil B will flow

Accepted Answer

When a switch is closed, allowing current to flow in coil A, electromagnetic induction causes a current to be induced in coil B only momentarily. This happens due to the change in magnetic flux that occurs when the current in coil A starts. Once the current in coil A reaches a steady state, the magnetic flux through coil B stops changing, and thus, the induced current in coil B stops as well.

Question 2

When there is a changing magnetic flux through an electric circuit, the direction of the induced current in the circuit is determined by _____________ Law.

Accepted Answer

The answer of When there is a changing magnetic flux...

Question 3

The unit used in expressing magnetic field strength is the __________.

Accepted Answer

The answer of The unit used in expressing magnetic field...

Question 4

A step-up transformer that doubles the input voltage is designed to work with an input voltage that varies at 60 Hz. The frequency with which the output voltage varies is ____________ Hz.

Accepted Answer

The answer of A step-up transformer that doubles the input...

Question 5

If a current of negative charge flows in a circle in the direction of one's curled fingers of the right hand, the resulting magnetic field would be in the direction

Accepted Answer

According to the right-hand rule, if a negative charge flows in the direction of the curled fingers, the magnetic field direction is opposite to the thumb.

Question 6

A bar magnet is held near a single closed loop of wire. The magnet is aligned with the loop axis, and the north pole is facing the loop. If the magnet is moved away, the current induced in the loop will be in a ______________ direction as viewed from the side the magnet is on.

Accepted Answer

The answer of A bar magnet is held near a...

Question 7

A solenoid carrying an electric current, if free to rotate when placed in a magnetic field, will tend to orient its axis _________________________________ (parallel, perpendicular, anti-parallel) to the magnetic field.

Accepted Answer

The answer of A solenoid carrying an electric current, if...

Question 8

Faraday's Law states that a voltage is induced in a circuit when there is a changing ___________________ passing through the circuit.

Accepted Answer

The answer of Faraday's Law states that a voltage is...

Question 9

Two parallel wires each carrying a current in opposite directions will __________________ one another.

Accepted Answer

The answer of Two parallel wires each carrying a current...

Question 10

What would happen if you had a car made completely of plastic, with no metal parts, and you drove over a vehicle sensor embedded in the road surface?

Accepted Answer

Vehicle sensors embedded in the road surface work by detecting changes in the magnetic field caused by the presence of metal objects such as cars. As a plastic car has no metal parts, the sensor would not detect it and therefore would not register the presence of the vehicle. This would result in the driver being stuck at the red light until another car with metal parts came along and triggered the sensor.

Question 11

The north pole of a bar magnet is moved away from a single closed loop of wire along the axis of the loop. The induced current in the loop produces an effective ____________ pole toward the bar magnet.

Accepted Answer

The answer of The north pole of a bar magnet...

Question 12

You could use two parallel wires to move objects 1 and 2 apart if each wire is embedded in its own object and if

Accepted Answer

When the currents in the wires are in opposite directions, they create a magnetic field that pushes the objects apart. This is known as the Lorentz force. If the currents were in the same direction, they would create a magnetic attraction between the wires, which would not move the objects apart. If one wire had zero current, there would be no magnetic field to create any force on the objects.

Question 13

You see a positively charged helium ion in space, and it is at rest with respect to your spacecraft. Since you are studying for the final exam, you decide to experiment. You slowly push the N pole of a bar magnet closer to the helium ion. What happens to the helium ion?

Accepted Answer

Magnetic fields exert forces on charged particles only when they are moving relative to the magnetic field. Since the helium ion is at rest with respect to the magnetic field, it will not experience a magnetic force.

Quiz 14: Magnets and Electromagnetism