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# The sensitivity of galvanometer depends upon which one of the following factors(A) Number of turns in the coil(B) Temperature of the room(C) Current flowing in it (D) Potential difference between two ends.

Last updated date: 19th Apr 2024
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Hint See the formula which is used for defining current sensitivity and voltage sensitivity.
The current sensitivity is given by
${I_s} = \dfrac{\theta }{I} = \dfrac{{NBA}}{K}$
Voltage sensitivity is given by
${V_s} = \dfrac{\theta }{V} = \dfrac{\theta }{{IR}} = \dfrac{{NBA}}{{KR}}$
Now, see the factors in which the current and voltage sensitivity depends.

The galvanometer is made sensitive, so that the needle of the galvanometer shows large deflection even when a small amount of current or small voltage is supplied across the coils.
There are two types of sensitive galvanometer in which the sensitivity of galvanometer depends:
Current Sensitivity- The deflection of a needle in a galvanometer due to passing of current in its coil is called current sensitivity. The current sensitivity is given by-
${I_s} = \dfrac{\theta }{I} = \dfrac{{NBA}}{K}$
where, $K =$torsion constant
$N =$ number of turns in the coil
$B =$ magnetic field
$\theta$ is the angle by which torque displace the coil
Voltage sensitivity- It is a deflection produced by a needle due to the potential difference applied across its ends. It is given by-
${V_s} = \dfrac{\theta }{V} = \dfrac{\theta }{{IR}} = \dfrac{{NBA}}{{KR}}$
From the above, we can conclude that sensitivity of galvanometer depends upon:
(1) Area of coil
(2) Magnetic field
(3) Torsion Constant
(4) Number of turns in a coil

Hence, the correct answer is option (A)

Note The device which is used to detect small electric current is called Galvanometer. In other words, we can say that the Galvanometer is used to measure the magnitude of electric current. The current is indicated by the movement of the magnetic needle. The coil of magnetic field is an important part of this device.