Question

A strong short bar magnet is dropped into a solenoid connected to a
galvanometer as shown in fig. The galvanometer shows a deflection to the left when the current in the coil as seen from above is counter clockwise. Which one of the following shows the correct deflection of the galvanometer when the magnet is at posi tions A, Band C.

Options

• At A	At B	At C
  left	left	left

• At A	At B	At C
  left	zero	zero

• At A	At B	At C
  left	zero	right

• At A	At B	At C
  left	right	left

• At A	At B	At C
  left	right	right

Answer 1

At A	At B	At C
left	zero	right

Explanation:

• At A: Left deflection.
• At B: Zero deflection.
• At C: Right deflection.

Reason: According to Lenz’s law, the induced current reverses direction as the magnet passes through the solenoid. At the middle position B, the change in magnetic flux is momentarily zero.