In a galvanometer 5% of the total current in the circuit passes through it . If the resistance of the galvanometer is G, the shunt resistance S connected to the galvanometer is

Options

A. 19 G
B. `(G)/(19)`
C. 20G
D. `(G)/(20)`

Answer

B

Explanation

`E= V+ Ir Rightarrow E = V+((V)/(R ))r`
When `V= 12V and R = 16Omega, E_1 = 12+ ((12))/((16))r…..(1)`
When `V= 12V and R = 10Omega, E_2= 11+((11)/(10))r….(2)`
`E_1= E_2 `(Given )
`12+((12)/(16))r= 11+((11)/(10)))r`
`Rightarrow 12-11= (11)/(10)r-(12)/(16)r`
`0.35r = 1Rightarrow r= (20)/(7)`