Which one of the following modifications may increase the senstivity of moving coil galvanometer?
`1^(st)` Way : By using spring of smaller torsion constant.
`2^(nd)` Way : By using a smaller coil
`3^(rd)` Way : By using a stronger magnet
`4^(th)` Way: By using a coil having fewer number of turns.

Options

A. `1^(st)` and `4^(th)` ways only
B. `1^(st)` and `3^(rd)` ways only
C. `1^(st)` and `3^(rd)` ways
D. `2^(nd)` and `4^(th)` only

Answer

B

Explanation

Sensitivity `=(BNA)/(K)`, by increasing B (stronger magnet) and decreasing torison constant, k (weaker springs)