Physics - Magnetism Question with Solution | TestHub

PhysicsMagnetismMagnetic torque & energyMedium2 minPYQ_2018
PhysicsMediumsingle choice

To increase the current sensitivity of a moving coil galvanometer by50 %,its resistance is increased, so that new resistance becomes twice its initial resistance, by what factor does its voltage sensitivity change?

Options:

Answer:
D
Solution:

New, current sensitivity, Is'=Is+50100Is

=150100Is=32Is

New resistance, R'=2 R

Initial voltage sensitivity, Vs=IsR

Now, new voltage sensitivity.

Vs=is'R'=32 Ic2 R=34Vs

% decrease in voltage sensitivity

=Vs-Vs'Vs×100

=1-VsVs×100

=1-34×100=25 %

Stream:BITSATSubject:PhysicsTopic:MagnetismSubtopic:Magnetic torque & energy
2mℹ️ Source: PYQ_2018

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