An experiment takes 10 min to raise the temperature of water in a container from 0 o C to 100 o C and another 55 min to convert it totally into steam by a heater supplying heat at a uniform rate. Neglecting the specific heat of the container and taking specific heat of the water to be 1 cal g ∘ C - 1 , the heat of vaporization according to this experiment will come out to be:

Step-by-step solution

Let the constant state of supply of heat per unit time = λ . So according to the first condition. λ t 1 = m c × 100   ⇒ λ m = 100 C t 1       . . . ( i ) , and according to the second condition, λ t 2 = m L f ⇒ λ m = L f t 2   . . . ( ii ) . By ( i ) and ( ii ) 100 C t 1 = L f t 2 ⇒ 1 cal × 100 10 = L f 55 ⇒ L f = 550   cal   g - 1