Question

An electric kettle takes 4a current at 220v. Howuch time will it take to boil 1kg of water from temperature 20°c ? The temperature of boiling water is 100°c.

Answer 1

Answer:

Given : m=1 kg=1000 g

Specific heat capacity of water S=1 cal/g.

o

C

Heat required, Q=mS(ΔT)=1000×1×(100−20)

Q=1000×80cal .......(1)

Heat produced in time t is, H=VIt

H=220×4×t Joule

H=

4.18

220×4×t

Cal ......(2)

Equating (1) and (2),

∴

4.18

220×4×t

=1000×80

⇒t=

220×4

1000×80×4.18

=380 s=6.3min.

Explanation:

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