An electromagnet becomes weaker when the amount of current through the coil increases.
Hence given statement is false.
The strength of the electromagnet can be increased by
(a) reversing the directions of current
(b) using an alternating current of high frequency
(c) increasing the current in the coil
(d) decreasing the number of turns of coil.
In an electric bell, when the electromagnet pulls the iron strip, it also breaks the circuit. The current through the coil stops flowing. In this case, will the coil remain an electromagnet? How does an electric bell ring then?
How does the magnetic field increase when we increase the number of coils in an electromagnet?