Question

# If the body A does a work in 20 s and body B does the same work in 40 s then, what is the ratio of their power respectively?

A

2:1

B

3:2

C

3:4

D

4:1

Solution

## The correct option is A 2:1 Let the power developed by body A = PA and  power developed by body B = PB Given, time taken by A, tA=20 s and time taken by B, tB=40 s. Power, P=Work doneTime taken As work done is constant or same, power is inversely proportional to time taken.  ⇒PAPB=tBtA=4020=21.  Hence, power ratio = 2:1.

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