Question

The time period of oscillation of a magnet in a vibration magnetometer is 1.5 seconds. The time period of oscillation of another magnet similar in size, shape and mass but having one-fourth magnetic moment than that of first magnet, oscillating at same place will be

• A. 0.75 sec
• B. 1.5 sec
• C. 3 sec
• D. 6 sec

Answer 1

Answer: (C)

3 sec

Answer 2

$T \propto \frac { 1 } { \sqrt { M } } \Rightarrow \frac { T _ { 1 } } { T _ { 2 } } = \sqrt { \frac { M _ { 2 } } { M _ { 1 } } } \Rightarrow \frac { 1.5 } { T _ { 2 } } = \sqrt { \frac { M _ { 1 } / 4 } { M _ { 1 } } } = \frac { 1 } { 2 }$

$\Rightarrow T _ { 2 } = 3 \mathrm { sec }$