NTA Abhyas JEE Main2020PhysicsMagnetic Properties of MatterPractice
A hoop and a solid cylinder of same mass and radius are made of a permanent magnetic material with their respective axes. But the magnetic moment of hoop is twice of solid cylinder. They are placed in a uniform magnetic field in such a manner that their magnetic moments make a small angle with the field. If the oscillation periods of hoop and cylinder are T h and T c respectively, then:
Options
- AT h = 2 T c
- BT h = T c
- CT h = 0.5 T c
- DT h = 1.5 T c
Correct answer
B. T h = T c
Step-by-step solution
Time period of any magnetic body place in an external magnetic field is:- T = 2 π I M B T h o o p = 2 π m R 2 M B ...... ( 1 ) I h o o p = m R 2 T c = 2 π m R 2 2 M 2 B ...... ( 2 ) I S o l i d c y l i n d e r = m R 2 2 From ( 1 ) and ( 2 ) T h = T c