Question

What will happen if the striker of a doorbell is kept in a magnetic field in a direction perpendicular to motion of striker.
A. Striker hits harder
B. Striker rebounds harder
C. More current is drawn
D. No effect

Answer 1

Hint: The contact point in the doorbell is the point where all electricity in the doorbell is controlled , as the striker moves, the circuit continuously and repeatedly closed and opened.

Complete solution :
An electric bell consists of an electromagnet , coils of insulating wire wound around iron rods.
When the electric current flows through the coils , the rods become magnetic and attract the piece of iron attracted to the clapper. This is the clapper that hits the bell and makes it ringing (tan-tan-tan-tan).
If the striker /clapper of a doorbell is kept in a magnetic field in a direction perpendicular to motion of striker then there will be no effect because striker is attracted towards the electromagnet if the circuit is complete and when we are applying the magnetic field perpendicular to the motion of the striker no effect is observed in the functioning of the doorbell.
Also the motion of the striker is unaffected by the applied perpendicular field .

Hence option (D) is the right answer.

For the bell to ring repeatedly , the striker must move in a back and forth motion. The rapid activation and deactivation of the electromagnets attracts the striker one moment and then releases it , this creates the vibratory motion, due to which the bell continues to ring (tan-tan-tan-tan).

Note:
In doorbells as the switch is pressed & the current is flowing in the circuit.
The electromagnetic coils which are inside of the doorbell can produce the painful electrical shocks if they are touched directly. A plastic shield is provided to just prevent this , but if this plastic cover/shield is lost or removed , do not touch the exposed coils.