In a ‘three pin plugs’, why is the earth pin made longer and thicker than the other pins?
A.) For proper electric position
B.) For greater efficiency
C.) To reduce heat losses
D.) For good look

Hint: The earth pin is longer because when we insert the plug into the socket, the earth pin will first come into contact with the power supply before the other two pins.

Complete step-by-step answer:
We have been asked why the earth pin is made longer and thicker than the other pins.
So, let us first know the three pin plugs.

The ‘three pin plugs’, has three pins which are the live pin, neutral pin and the earth pin.
Among these three pins (live, neutral and earth), the earth pin is made longer and thicker than the other two pins, so that when we insert the plug into the socket, the earth pin comes into contact with the power supply before the other two pins, this is because if any unwanted charges are there then they will be removed (grounded) before the other two pins will go inside the terminals.

This will ensure that if we connect the earth first then that will increase our safety and the device's safety if any fault occurs.

Also, the earth pin is made thicker so that even by mistake also it cannot be inserted into the holes for the live or neutral connection of the socket.

So, this increases the efficiency.
So, the correct option is B.

Note: Whenever such types of questions appear then first know about the three pin plugs, about the pins and their names. Then as mentioned in the solution, the earth pin is made longer and thicker to ensure our safety if any fault occurs. This increases the efficiency.