On a 600 W electric stove with an efficiency of 45%, 1500 cm3 of water taken at 10 ° C

On a 600 W electric stove with an efficiency of 45%, 1500 cm3 of water taken at 10 ° C was heated to boiling, and 45 cm3 was turned into steam. How long the heating took.

Specific heat capacity of water – 4183 J / kg;

Specific heat of evaporation of water – 2260 kJ / kg;

The density of water is assumed to be 1 g / cm3;

Let’s find the amount of heat spent on heating and evaporating water:

Q = Sud * m * (T2 – T1) + Qtest * mtest = 4183 * 1.5 * (100 – 10) + 2260000 * 0.045 = 666405 J;

Let’s find the total amount of heat spent in the process:

Qtot = Q / efficiency = 666405 / 0.45 = 1480900 J;

The heating time will be:

t = Q / W = 1480900/600 = 2468 s = 41.14 min.

Answer: t = 41.14 minutes.