Magnetism Question 98
Question: A tangent galvanometer has a coil with 50 turns and radius equal to 4 cm. A current of 0.1 A is passing through it. The plane of the coil is set parallel to the earth’s magnetic meridian. If the value of the earth’s horizontal component of the magnetic field is $ 7\times {{10}^{-5}} $ tesla and $ {\mu _{0}}=4\pi \times {{10}^{-7}}weber/amp\times m $ , then the deflection in the galvanometer needle will be
[MP PMT 1993]
Options:
A) 45o
B) 48.2o
C) 50.7o
D) 52.7o
Show Answer
Answer:
Correct Answer: B
Solution:
For tangent galvanometer $ I=\frac{2rB}{{\mu _{0}}n}\tan \theta $
$ \
Therefore \ \tan \theta =\frac{I{\mu _{0}}n}{2rB}=\frac{0.1\times 4\pi \times {{10}^{-7}}\times 50}{0.04\times 7\times {{10}^{-5}}\times 2}=1.12 $ or $ \theta ={{\tan }^{-1}}( 1.12 )={{48.2}^{o}} $
BETA
