Question

A bar magnet falls from a height 'h' through a metal pipe, its acceleration after coming out of pipe is

• A. less than \(9.8\text{ m/s}^2\)
• B. greater than \(9.8\text{ m/s}^2\)
• C. equal to \(9.8\text{ m/s}^2\)
• D. equal to 'h' \(\text{m/s}^2\)

Hint:

Eddy current braking stops once the magnet leaves the pipe.

Answer 1

The Correct Option is C

Step 1: Inside versus outside:
Inside: eddy currents give a retarding force. Outside: none.

Step 2: Force:
Outside the pipe the only force is $mg$, so $a=g$.

Step 3: Pick:
Option (C).

Final Answer:
The braking effect exists only inside the pipe. \[ \boxed{C} \]