Question

An electric kettle of 1500 words waiting boils at certain quantity of water and 5 minutes the heat which is generated for boiling is water?

Answer 1

Answer:

Power of an electric kettle = 1500 W = 1500 J/s

Time for boiling the water = 5 minutes = 5 * 60 sec = 300 sec

We know from the definition that the heat energy generated is given by the power delivered in unit time where the SI unit of heat energy is Joules(J), power is Watt(W) or Joules/second(J/s) and time is second(s).

Let us assume that the electric kettle is 100% efficient i.e., it will deliver the exact amount of the watt rating that it should according to the data in the questions and thereby putting the given value to get the amount of heat generated,

∴ Heat energy = Power * time

⇒ Heat energy = 1500 J/s * 300 s = 450000 J = 450 kJ

Hence, 450 kJ of heat is generated for boiling the water.