JEE Main On 16 April 2018 Question 6
Question: In a circuit for finding the resistance of a galvanometer by half deflection method, a 6V battery and a high resistance of $ 11,k\Omega $ are used. The figure of merit of the galvanometer $ 60\mu A/division. $ In the absence of shunt resistance, the galvanometer produces a deflection of $ \theta =9 $ divisions when current flows in the circuit. The value of the shunt resistance that can cause the deflection of $ \theta /2, $ is closest to [JEE Main 16-4-2018]
Options:
A) $ 55\Omega $
B) $ 110\Omega $
C) $ 220\Omega $
D) $ 550\Omega $
Show Answer
Answer:
Correct Answer: B
Solution:
(i) r is not there. $ I=9\times 60\mu A $ $ \frac{6}{11000+G}=540\times {10^{-6}} $
$ G=\frac{1000}{9} $ (ii)
$ G=\frac{RS}{R-S} $
$ \frac{1000}{9}=\frac{11000S}{11000-S} $ This gives S = 110
