(a) A device that is used to break an electric circuit is called a switch.
Switch:
A switch is an electric device that is used to break a circuit. When the switch is in 'OFF' position, then the circuit is not complete. Then, the circuit is called an open circuit. An electric current cannot flow through this circuit.
(b) An electric cell has two terminals.
Two terminals:
An electric cell has two terminals, a negative terminal and a positive terminal (as shown in the given figure).
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