NTA Abhyas JEE Main2020PhysicsMagnetic Properties of MatterPractice
A magnet makes 40 oscillations per minute at a place having magnetic field induction of 0.1 × 10 – 5 T . At another place, it takes 2.5 s to complete one vibration. The value of earth's horizontal field at that place is
Options
- A0.25 × 10 – 6 T
- B0.36 × 10 – 6 T
- C0.66 × 10 – 8 T
- D1.2 × 10 – 6 T
Correct answer
B. 0.36 × 10 – 6 T
Step-by-step solution
T = 2 π I M × B H ⇒ T ∝ 1 B H ⇒ T 1 T 2 = ( B H ) 2 ( B H ) 1 ⇒ 60 / 40 2.5 = ( B H ) 2 0.1 × 1 0 - 5 ⇒ ( B H ) 2 = 0.36 × 1 0 - 6 T