A galvanometer of resistance `50Omega` is connected to a b attery of 3V alongwith a resistance of `2950Omega` in series. A full scale deflection of 30 division is obtained in the galvanometer in order to reduce this deflection to 20 division. The resistance in sereis. should be:-

Options

A. `6050 Omega`
B. `4450 Omega`
C. `5050 Omega`
D. `5550 Omega`

Answer

C

Explanation

`I prop 1/R`

`rArr i_(1)/i_(2) = R_(2)/R_(1) rArr 30/20 = (3000 + R)/3000`
`rArr 9000 = 6000 + 2R rArr R = 1500 Omega`
Total resistance `= 2950 + 1500 = 4450 Omega`