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:-

Answer

A

Explanation

`x_(cm) = (int xdm)/(int dm)`
`rArr (7L)/(12) = (int_(0)^(L)x(a + (bx)/(L)) dx)/(int_(0)^(L) (a + (bx)/(L)) dx)`
Solving we get `2a = b`