Question

The voltage range of the Galvanometer of resistance R is 0 to 1V. When it's range increases up to 2V, for this the additional resistance required in series will be :

Answer 1

It has given that, voltage range of galvanometer of resistance R is 0 - 1 V. its range increases upto 2V

To find : for this the additional resistance required in series will be ....

solution : resistance of galvanometer = R

potential across galvanometer = 1 volt

let i_g is the current passing through galvanometer.

i_g × R = 1

I_g = 1/R ..........(1)

Let R₁ is connected in series with galvanometer.

so new potential across system of resistor and galvanometer = 2 volts.

so, i_g × (R₁ + R) = 2

⇒1/R (R₁ + R) = 2 [ from equation (1). ]

⇒R₁ = R

Therefore the additional resistance required in series will be R. i.e., correct option is (1)