Magnetism Question 136

Question: The radius of the coil of a Tangent galvanometer. which has 10 turns is 0.1m. The current required to produce a deflection of 60° $ (B _{H}=4\times {{10}^{-5}}T) $ is

[MP PET 2005]

Options:

A) 3 A

B) 1.1 A

C) 2.1 A

D) 1.5 A

Show Answer

Answer:

Correct Answer: B

Solution:

$ B=B _{H}\tan \theta $

Therefore $ \frac{{\mu _{0}}ni}{2r}=B _{H}\tan \theta $

Therefore $ i=\frac{2r.\ B _{H}\tan \theta }{{\mu _{0}}n} $

$ =\frac{2\times 0.1\times 4\times {{10}^{-5}}}{10\times 4\pi \times {{10}^{-7}}} $ = 1.1A