Physics
The diagram in figure shows a three pin plug. Label the three pins.
(a) Why is top pin thicker and longer than the other two?
(b) Why are the pins splitted at the ends?
Answer
In a three pin plug, the top pin is for earthing, the pin on the left is for live and the pin on the right is for neutral. In the good quality plugs, these are marked as E, L and N respectively.
(a) The earth pin is thicker and longer than the other two. The earth pin is made long so that the earth connection is made first. This ensures the safety of the user because if the appliance is defective, then as soon as the live pin gets connected, the current passes to the earth and the fuse blows off.
Further, the pin is made thicker so that even by mistake it cannot be inserted into the hole of live or neutral connection.
(b) The pins are splitted at the ends to provide a spring action so that they fit in the socket holes tightly.
Related Questions
It is dangerous to connect the switch in the neutral wire. Explain your answer.
(a) A switch is not touched with wet hands while putting it on or off. Give a reason for your answer.
(b) Name the wire to which a switch is connected.
To which wire is the metallic case of an electric appliance connected? Give the reason?
(a) The earthing of an electric appliance is useful only if the fuse is in the live wire. Given the reason.
(b) Name the part of the appliance which is earthed.