Question

The period of oscillations of a magnet is 2 sec. When it is remagnetised so that the pole strength is 4 times its period will be

• A. 4 sec
• B. 2 sec
• C. 1 sec
• D. 1/2 sec

Answer 1

Answer: (C)

1 sec

Answer 2

$T \propto \frac { 1 } { \sqrt { M } } \Rightarrow T \propto \frac { 1 } { \sqrt { m } }$; If $m \rightarrow 4$ times.

$T ^ { \prime } = \frac { T } { 2 } = \frac { 2 } { 2 } = 1 \mathrm { sec }$