Question

A galvanometer shows full scale deflection for a current I_g. If a shunt of resistance S₁ is connected to the galvanometer, it gets converted into an ammeter of range (0 - I). When resistance of the shunt is made S₂, its range becomes (0 - 2I). Then `(S_1/S_2)` is ______.

Options

• `(I + I_g)/(I - I_g)`

• `(I - I_g)/(I + I_g)`

• `(2I - I_g)/(I - I_g)`

• `(I - I_g)/(2I - I_g)`

Answer 1

A galvanometer shows full scale deflection for a current I_g. If a shunt of resistance S₁ is connected to the galvanometer, it gets converted into an ammeter of range (0 - I). When resistance of the shunt is made S₂, its range becomes (0 - 2I). Then `(S_1/S_2)` is `bbunderline((2I - I_g)/(I - I_g))`.

Explanation:

Since, `S = (I_gG)/((I - I_g))`

Case-1: `S_1 = (I_gG)/((I - I_g))`

Case-2: `S_2 = (I_gG)/(2I - I_g)`

Now, `S_1/S_2 = (2I - I_g)/(I - I_g)`