Question

Two tangent galvanometer A and B are identical except in their number of turns .They are conducted in series on passing on a current through them , defections of 60 and 30 degrees are produced .The ratio of number of turns in A and B is


1)1:3


2)3:1


3)1:2


4)2:1

Answer 1

answer : option (2) 3 : 1

explanation : both the galvanometers are joined in series combination. so, current through each galvanometer is same.

so, number of turns is directly proportional to tanθ

where , θ is deflection produced in galvanometer.

so, $\frac{N_1}{N_2}=\frac{tan\theta_1}{tan\theta_2}$

= tan60°/tan30°

= (√3)/(1/√3)

= 3/1

hence, ratio of number of turns in A and B is 3 : 1