Question

Symbol of the open switch is
A. 

B. 

C. 

D. 

Answer 1

Hint: A switch is used in a circuit to break the flow of current or block the flow of current through a certain branch or part of the circuit. Switches are used by us daily to turn on and off the electrical appliances according to our needs. To make a simplified circuit diagram we need to denote a switch with something easy to draw and understand.

Complete answer:
A switch has a mechanism which disconnects the two wires between which it is placed. This can simply be achieved by disconnecting the wires but that is unsafe and also difficult. So, switches were invented which do just that without posing any danger to the user and are also easy to operate. A simple switch can be made by placing an insulated strip of metal between the two ends of the wire to be connected. The symbol for the switch looks like that only. For a closed switch the symbol looks like this 

. As you can see this looks like another wire placed between the two wires. In this condition, current can flow through the switch and it is called closed as in this condition the circuit is closed. When we disconnect the wire from one side, the switch will look like this 

. It is called open in this condition as the circuit is open and the flow of current is restricted.

Hence the correct option is C, i.e. 

Note: Students must take care that although in common language when an appliance is being operated and is in the on the condition, we call the switch to be open. This may be misleading and an open switch in physics actually means what we commonly call as the closed switch.