Q. Two tangent galvanometer A and B are identical except in their number of turns. They are connected in series. On passing a current through them, deflections of 60° and 30° are produced. The ratio of the number of units A and B is
A) 1:3
B) 3:1
C) 1:2
D) 2:1
Explanation
(b) As the current and the other factors are same for both the galvanometers
$N\ \propto \tan\theta$
$\frac{N_{1}}{N_{2}} = \frac{\tan{60{^\circ}}}{\tan{30{^\circ}}} = \frac{\sqrt{3}}{1/\sqrt{3}}$
$\Longrightarrow \ \ \frac{N_{1}}{N_{2}} = 3$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.