QUESTION
 

Asked by gpnkumar0 | 2nd Oct, 2017, 10:57: AM

Expert Answer:

The heat supplied to the kettle by the mains is H = VIt
 
Now, this heat is used to boil the water from 20 °C to 100 °C.
 
This heat used up is Q = mcΔT
 
Now, according to principle of calorimetry, H = Q.
 
VIt = mcΔT
t = (mcΔT)/VI = (1 × 4.2 × 103 × (373 - 293))/(220 × 4) = 381.8 s = 381.8/60 = 6.3 min
 
Hence, the correct answer is option C.

Answered by Romal Bhansali | 25th Oct, 2017, 03:43: PM