Bihar Police Constable Model Paper 1

• The unit of power is the watt, and hence the unit of energy is watt-second since energy is the product of power and time.
• The watt-second is referred to as joules.
• One watt-second is equal to 1/3,600 of a watt-hour or one joule.
• The dimensions of energy are [ML2T–2] which is the same as work.
• The SI unit joule (J) is named after the famous British physicist James Prescott Joule (1811-1869).

Hence, from the above points, we can clearly infer that Watt second is the unit of energy.