Question

Why is soft iron core used in galvanometers?

Answer 1

Hint: We should know that, a galvanometer is a device which is used to measure and detect the small currents flowing in the electrical circuits and a soft iron core is a magnetic material that has low carbon content and is easily magnetized and demagnetized in the presence of magnetic field. We will discuss the principle of working of galvanometer and figure out why soft iron core is best to use in galvanometer.

Complete answer:
A galvanometer works on the principle that whenever a current carrying coil is placed inside the magnetic field, the current carrying coil experiences a torque which in turn rotates and this deflection of the coil mainly depends upon the strength of the current.

In order to produce magnetic field inside the galvanometer device, we can use any magnetic material but soft iron core is especially used in galvanometer because Soft iron is ferromagnetic in nature which in turn strengthen the magnetic field lines, and stronger the magnetic field lines passing through the coil larger the sensitivity of the galvanometer.

Hence, a soft iron core is used to increase the sensitivity of the galvanometer.

Note: It should be remembered that sensitivity of the galvanometer is the deflection produced in the moving coil per unit current passing through it and this sensitivity is directly proportional to the magnetic field lines passing through the moving coil of the galvanometer.Also, ferromagnetic substances are those which when placed in magnetic field and later when removed out from magnetic field they exhibit the properties of magnetism which means they also behave as a magnetic material.