Quiz #5

 Cheat Sheet:
¯   ¯   ¯  

		  		  

		If an equation you need is not listed here, ask.

Multiple choice: 1 pt. each

1. Which of the following is NOT a way to change the magnetic flux through a coil in a constant magnetic field?

* A. Add another turn in the coil.

B. Change the directional orientation of the coil.

C. Change the area within the coil.

D. Change the magnetic field through the coil.

2. A Henry is

A. a unit of emf.

* B. a unit of inductance.

C. a unit of magnetic field.

D. a nickname for a physics nerd.

3. Inductors

A. cause the current to jump up suddenly when the switch in an RL circuit is closed.

B. never have a voltage drop across them.

* C. have no effect in circuits with constant current.

D. are made of insulating material.

4. Lenz's Law provides a way of finding

A. the magnitude of the magnetic field inside a loop.

B. the magnitude of the induced current around a loop.

C. the direction of the magnetic field inside a loop.

* D. the direction of the induced current around a loop.

5. The magnetic flux through a loop is increased so that more flux is coming out toward you. Which of the following happens?

* A. A current is induced clockwise around the loop.

B. No current is induced.

C. A current is induced counterclockwise around the loop.

D. Unknown. More information is needed.

6. In which of the following cases is an emf induced across the ends of a metal rod in a constant magnetic field B?

A. The velocity of the rod is parallel to B, and the rod is parallel to B.

B. The velocity of the rod is parallel to B, but the rod is perpendicular to B.

C. The velocity of the rod is perpendicular to B, but the rod is parallel to B.

* D. The velocity of the rod is perpendicular to B, and the rod is perpendicular to B.

7. A loop of area 1 m is initially oriented parallel to a constant magnetic field of 5 T (i.e. the plane of the loop is perpendicular to the magnetic field). If the loop has a resistance of 0.5 and is rotated at a rate of 2 rev/s about its diameter, what is the induced current in the loop as a function of time? (4 pts.)

rad/s