Thermal Properties of Matter - Result Question 27

28. An electric kettle takes 4A current at 220V. How much time will it take to boil 1kg of water from temperature 20C ? The temperature of boiling water is 100C.

(a) 6.3min

(b) 8.4min

(c) 12.6min

(d) 4.2min

[2008]

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Answer:

Correct Answer: 28. (a)

Solution:

  1. (a) Heat required to raise the temperature of 1kg water from 20C to 100C is given by Q=msΔθ=(1×4200×80)J

Power of kettle (P)=VI=(220×4)W

Time taken =QP=1×4200×80220×4

=381.81sec=6.36min



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