Question

The bell shown in the picture works the same way that a doorbell works. The bell only rings when the electromagnet pushes on the beater bar. The magnetic force moves the beater bar so that it rings the bell.


Most of the time, the bell does not ring because the electromagnet is off. What turns the electromagnet on when a person pushes the doorbell button?
A.
a current in the coil of the electromagnet
B.
a build up of static charge
C.
the movement of another magnet
D.
the energy of the person's finger

Answer 1

A. a current in the coil of the electromagnet

When the button is pushed it closes the electrical circuit so current flows through the coil. That current creates the magnetic field (turns the electromagnet on) and pulls the beater to ring the bell.