Describe the working principle of a moving coil galvanometer. Why is necessary to use
(i) a radial magnetic field and
(ii) a cylindrical soft iron core in a galvanometer ?
Write the expression for current sensitivity of the galvanometer .
Can a galvanometer as such be used for measuring the current ? Explain.

Explanation

Working and Principle of moving coil galvanometer
Necessity of (i) radial magnetic field
(ii) cylindrical soft iron core
Expression for current sensitivity
Explanation of use of Galvanometer to measure current.
When a coil, carrying current, and free to rotate about a fixed axis, is placed in a uniform magnetic field, it experiences a torque (Which is balanced by a restoring torque of suspension).
(i) To have deflection proportional to current/ to maximize the deflecting torque acting on the current carrying coil.
(ii) To make magnetic field radial/to increase the strength of magnetic field.
Expression for current sensitivity.
`I_(s)=(theta)/I` or `(NAB)/K`
where `theta` is the deflection of the coil
No
The galvanometer, can only detect current but cannot measure them as it is not calibrated. The galvanometer coil is likely to be damaged by currents in the (mA/A) range]