JEE Main & Advanced
JEE Main Paper (Held On 9 April 2016)
question_answer
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\[\theta .\]If a shunt of resistance S is needed to gat half deflection then G, R and S are related by the equation :
JEE Main Online Paper (Held On 09 April 2016)
A)2S = G
B)2G = S
C)S(R+G) = RG
D)2S(R+G) = RG
Correct Answer:
C
Solution :
Case-1 Case-2 \[{{i}_{1}}=\frac{{{V}_{E}}}{R+G}\] \[i=\frac{{{V}_{E}}}{R+\frac{GS}{G+S}}\] \[\frac{{{i}_{1}}}{2}G=\left( i-\frac{{{i}_{1}}}{2} \right)S\] \[{{i}_{1}}(G+S)=2iS\] substituting \[{{i}_{1}}\] and i we get S(R+G) = RG