Two coils of insulated copper wire are wound over a non conducting cylinder as shown. Coil I has larger number of turns.

(i) Write your observations when,
(a) key K is dosed,
(b) key K is opened,
(ii) Give reason for your observations.
(iii) Mention the name of the phenomenon involved and define it.
(iv) Name of two coils used ln this experimenl
(v) State the rule which gives the direction of induced current

Explanation

(i) (a) A momentary deflection is shown by the galvanometer.
(b) A momentary deflection is shown by the galvanometer but in the opposite direction.
(ii) When key is closed or opened, the current in the coil I changes, therefore the magnetic field linked with coil Il changes and hence a current is induced in it.
(iii) Electromagnetic induction : The process by which a changing magnetic field in a conductor induces current in another conductor.
(iv) Primary coil : coil I
Secondary coil : coil II
(v) Fleming.s Right Hand Rule : Stretch the first three fingers of the right hand mutually perpendicular to each other such that the forefinger gives the direction of magnetic field and the thumb points in the direction of the motion of a conductor then, the middle finger will give the direction of the induced current.