Question

What is the reduction factor of galvanometer . The amount of of current required to produce 45∘ deflection in a galvanometer is defined as it reduction factor.

Answer 1

Solution :
Given I1=10mA,θ1=31∘,θ2=42∘
I2I1=tanθ2tanθ2
=>I2=I1tanθ2tanθ1
=10×tan42∘tan31∘
=10×0.90.6
=15mA
Percentage increase in current (I2−I1)I1
=15−1010×100
=50%

Answer 2

I=Ktanθ, where K is the reduction factor and θ is the deflection.

=>K= 1/tanθ

=> K=I for θ=45

So reduction factor will be equal to current passing through galvanometer to produce a deflection of 45