JEE Main 2016 · 9 Apr · Shift 1 · Physics Q27

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PhysicsSingle correct+4 / -1Question 27 of 90

To know the resistance G of a galvanometer by half deflection method, a battery of emf $V_E$ and resistance R is used to deflect the galvanometer by angle θ. If a shunt of resistance S is needed to get half deflection then G, R and S are related by the equation :

2S (R + G) = RG

S (R + G) = RG

2S = G

2G = S

Answer and worked solution

Official answer: B

Without shunt, $I_g=\frac{V_E}{R+G}$ . With the shunt the galvanometer current is $\frac{V_ES}{R(G+S)+GS}$ . Setting this to half: $2S(R+G)=RG+RS+GS$ , i.e. $S(R+G)=RG$ .

Topics:Galvanometer experiments

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JEE Main 2016 · 9 Apr · Shift 1, Physics question 27