Question text
21 The diagram shows an electromagnet. d.c. supply + – A metal core How can the strength of the magnetic field around the electromagnet be increased? A Remove the metal core and decrease the current in the circuit B Remove the metal core and keep the current in the circuit constant C Reverse the d.c. supply and decrease the current in the circuit D Reverse the d.c. supply and increase the current in the circuit
21 The diagram shows an electromagnet.
d.c. supply
+ –
A
metal core
How can the strength of the magnetic field around the electromagnet be increased?
A Remove the metal core and decrease the current in the circuit
B Remove the metal core and keep the current in the circuit constant
C Reverse the d.c. supply and decrease the current in the circuit
D Reverse the d.c. supply and increase the current in the circuit
Select your answer: