Physics Problem Set 8 (Ch. 14)

Two current-carrying wires are parallel to one another and separated by 1 cm. If the distance between them is increased to 2 cm the new force will be what factor times the original force?

1/2

A transformer is to be used to step down voltage from an alternating current source from 220 V to 110 V. If the primary has 120 turns, then the number of turns in the secondary is

60

A long straight wire carries a current. A positive charge moves toward the wire in a direction perpendicular to the wire. The direction of the force on the charge will be

parallel to the wire opposite the direction of the current.

Two particles move into a magnetic field. They enter moving at the same speed and direction. The magnitude of the charge on each is known to be the same. One particle curls to the right and the other to the left upon entering the field, the one on the left moving in a larger circle than the one on the right. From this we can say that

the leftward moving particle has more mass and its charge is opposite the other particle.

Two long bar magnets are aligned so that north poles face each other. The magnets are separated by 1 cm, and a repulsive force between the north poles is 0.04 N. When the separation is increased to 2 cm the force will be

.010 N

The south pole of a bar magnet is moved toward a short helical coil of wire (solenoid) along the axis of the coil. The coil has 100 turns and the ends of the coil are connected to form a closed circuit. If the coil is replaced with a single loop of the same type of wire, and the magnet is moved exactly as before, the current induced in the loop is

100 times smaller

A battery is causing a large current in a solenoid (helical coil of wire). A bar magnet is held at rest nearby, aligned with the axis of the solenoid, with its south pole closest to the solenoid. The bar magnet is being repelled by the solenoid. Which of the following statements is true of the conventional current in the solenoid?

The current in the solenoid is flowing clockwise as seen from the bar magnet.

A bar magnet is broken in half and the magnetic field around one piece is mapped out. What is wrong with this picture?

There is no south pole.

The magnetic pole near the Earth's north geographic pole actually has to be

an S pole, because it attracts the N pole of your compass needle.

Two identical coils of wire are placed on a single horizontal wooden broom handle. The coils are separated by a few centimeters. We now run identical currents in the same direction through each coil. The coils experience

an attractive magnetic force.

The south pole of a bar magnet is moved toward an aluminum ring, along the axis of the ring. As the magnet approaches, the changing magnetic flux induces an electric current in the ring that, when seen from the bar magnet, corresponds to positive charge carriers flowing

clockwise

Imagine that this classroom contains a constant magnetic field that points from the front to the back. In front of you a negative charge is slowly moving horizontally to your left. As you watch, the magnetic force on the charge

defects the charge into a counterclockwise vertical circle

The south pole of a bar magnet is moved toward a short helical coil of wire (solenoid) along the axis of the coil. The coil has 100 turns and the ends of the coil are connected to form a closed circuit. If the coil is replaced with a single loop of the same type of wire, and the magnet is moved exactly as before, the magnet experiences a force that is

repulsive and 100 times smaller.