A) \[{{90}^{o}}\]
B) \[{{60}^{o}}\]
C) \[{{45}^{o}}\]
D) \[{{30}^{o}}\]
Correct Answer: B
Solution :
Key Idea: In vertical plane in magnetic meridian both horizontal and vertical components of magnetic field exist. When M is magnetic moment of the magnet, H and V are the horizontal and vertical components of earths magnetic field and I is moment of inertia of magnet about its axis of vibration, then the time-period of-magnet is \[T=2\pi \sqrt{\frac{I}{MH}}\] when horizontal component is taken \[T=2\pi \sqrt{\frac{I}{MB}}\] [as in vertical plane in magnetic meridian both V and H act on the needle]You need to login to perform this action.
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