How much time will be required to perform 20 J of work at the rate of 20 W?
Correct answer: A. 1 sec
- A. 1 sec
- B. 4 sec
- C. 8 sec
- D. 10 sec
Explanation
As P=W/t , Therefore,t=W/PUsing valuest= 20/20t= 1 secSo, this option is right.
Last updated
About Power
Power is the rate at which work is done or energy is transferred, with average power calculated over a time interval and instantaneous power found from P = Fv when force and velocity are aligned. Work includes units, mechanical efficiency, and the distinction between power and total work or energy.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
100 joules work has been done by an agency in 10 seconds. What is the power of agency?
1KWh= _ J?
A 200N force acts on 8 kg crate that starts from rest. At the instant the object has gone 2m, the rate at which the force is doing work is:
A heater is used for 5 minutes to heat 500 g of water from 20˚C to 50˚C. What is the power of heater? Specific heat capacity of water is 4.2 J/gC.
A lamp is connected to a 12-volt battery. An ammeter indicates a current of 5 mps. The watt of the lamp is: