PHYSICS Q4M1 Flashcards


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created 8 months ago by mags
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1

1. A strong permanent magnet is plunged into a coil and left in the coil. What is the effect produced on the coil after a short time?

there is no effect

2

2. The Law that states that the direction can induced current is such that its own magnetic field opposes the original change in magnetic flux that induced the current.

Lenz's law

3

3. Lenz’s law concerning the direction of an induced current in a conductor by a magnetic field could be a restatement of?

Law of Conservation of Energy

4

4. To determine the directions of the induced magnetic fields, currents, and emfs the following steps are observed EXCEPT

make a sketch of the situation for use in visualizing and recording directions

5

5. A permanent magnet is dropped, south pole-down, through a conducting loop as shown. As the magnet falls toward—and then falls past—the area of the loop, what will be the direction of the current flow?

Clockwise when falling toward, but counterclockwise as falling away

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6. A circular loop of wire is placed in a magnetic field as show below. If the magnetic field is increasing, what direction is the induced current in?

counterclockwise

7

7. A loop of conducting wire with length L and width W is entering a magnetic field B at velocity v. What direction will the induced current travel in?

counterclockwise

8

8. What is the direction of the magnetic force on the loop as it enters magnetic field B?

up

9

9. A loop of wire sits in an unchanging magnetic field. Which of the following is a NOT a way to induce a current through the loop?

Spin the loop about its center

10

10. Which of the following statements is NOT true about DC current flow?

All DC powered items need to be plugged in.

11

11. The unidirectional current is called

direct current

12

12.The supply of electrical energy for a consumer is usually by AC because

the voltage drop in cables is minimal

13

13. Why is alternating current transfer more effective than dc current transfer over long distances?

due to step-up and step-down transformers reducing I2R losses

14

14. AC is produced by a generator and its charge is

negative and positive

15

15. The amount of force the electrons are moved in a circuit is called _______.

emf