1.

If the current sensitivity of a galvanometer is doubled, then its voltage sensitivity will beA. doubledB. halvedC. unchangedD. four times

Answer» Correct Answer - C
Current sensitivity of galvanometer is deflection per unit current i.e.
`(phi)/(I)=(NAB)/(k)" …(i)"`
Similarly voltage sensitivity is deflection per unit voltage
i.e. `(phi)/(V)=((NAB)/(k))(I)/(V)=((NAB)/(k))=(1)/(R)" ...(ii)"`
From (i) and (ii)
Voltage sensitivity `="current sensitivity"xx(1)/("resistance")`
Now if current sensitivity is doubled, then the resistance in the circuit will also be doubled since it is proportional to the length of the wire, then voltge sensitivity
`=(2xx"current sensitivity")xx(1)/((2xx"resistance"))`
`="(current sensitivity)"xx(1)/("(resistance)")`
Hence, voltage sensitivity will remain unchanged.


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