magnetic field

Question 1

Answer 1

The loop means that the current acts in two opposite directions

Question 2

Answer 2

Question 3

Answer 3

the primary coil is connected to a DC power source. This means:
When the switch is first closed, the current in the primary coil suddenly increases from 0 to some value. This creates a changing magnetic field, which induces a temporary voltage in the secondary coil.
After the current becomes steady, the magnetic field stops changing. Since the induced EMF depends on the rate of change of the magnetic field, the voltage in the secondary coil drops back to zero.
If the switch were later opened, the current in the primary would suddenly drop to zero, causing another temporary change in the magnetic field and inducing another momentary voltage in the opposite direction.

Question 4

Answer 4

Question 5

Answer 5

Understanding that emf is the rate of change, that’s why it becomes positive /negative

Question 6

Answer 6

Question 7

Answer 7

Question 8

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Answer 8

Question 9

If the scale reads a positive value, what direction is the force from the motor effect acting in ?

Answer 9