Question

The main function of switch is to:
A. Allow charges to flow
B. Complete or break a circuit
C. Make the bulb glow easily
D. Prevent electric shocks

Answer 1

Hint: In order to solve a question we need to understand the flow of current and effect of it. Current is defined as the number of charges crossing per unit cross sectional area and it flows due to potential difference across wire. When a wire is connected across potential difference then an electric field sets up in it in the direction of decreasing electric field thereby forcing electrons to drift in opposite direction and hence a current flows in direction opposite to direction of flow of electrons. Current flowing in the circuit produces heat which may damage wire and electric equipment attached to it.

Complete step by step answer:
As stated current flows in circuits having resistance produces heating effects which may damage the electrical equipment connected in a given circuit like the inductor, capacitor etc.So a check on current needs to be there in circuit to prevent the damage of electrical equipment.

So a switch is used in the circuit. Switch is an electrical device and its main function is to have a control on stop or flow of current thereby either breaking or completing the circuit. When the switch is open it breaks the circuit by stopping current to flow but when the switch is closed then it completes the circuit by allowing it to flow. Transistor can also be considered as a switch and it is mostly known as a digital switch.

Note: It should be remembered that the construction of switch is such that when the switch is open then the wire in switch loses contact with circuit so current flow stops but when a switch is connected then due to contact current flows. Any insulator or dielectric can be used to prevent a shock from current like slippers etc.