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Water of volume 2 litre in a container i...

Water of volume 2 litre in a container is heated with a coil of `1kW at 27^@C.` The lid of the container is open and energy dissipates at rate of `160J//s.` In how much time temperature will rise from `27^@C to 77^@C` Given specific heat of water is
`[4.2kJ//kg`]

A

8 min 20 s

B

6 min 2 s

C

7 min

D

14 min

Text Solution

Verified by Experts

The correct Answer is:
A
Heat gained by the water + Heat dissipated to environment = Heat supplied by the coil
`implies ms Delta theta+P_("Loss")t=P_("coil") xx t`
`implies 2xx4.2 xx10^3(77-27)=1000t-160t`
`t=(4.2 xx 10^5)/(840)=500` sec = 8 min 20 sec
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