Calculate the amount of energy wasted on combustion of 2 kg of diesel in a diesel engine of efficiency 40% The calorific value of diesel is `44,800 kJ//kg`.

Find the work done by a petrol engine on combustion of 1 kg petrol. The efficiency of the engine is 30% and calorific value of petrol is 47 MJ kg^(-1).

60 MJ energy is produced on combustion of 2 kg of coal. Find how much energy is produced on burning 0.5 kg of coal. Also find the calorific value of coal.

Calculate the amount of heat energy to be supplied to convert 2 kg of ice at 0^@C completely into water at 0^@C if latent heat of fusion for ice is 80 cal/g.

Assuming the splitting of U^235 nucleus liberates 200 MeV energy, find (a) the energy liberated in the fission of 1 kg of U^235 and (b) the mass of the coal with calorific value of 30 kJ//g which is equivalent to 1 kg of U^235 .

Some words (underlined) in the following sentences are jumbled up. Write them in their correct form. (a) underline("Seldie") is a combustible substance. (b) underline("Slags") is a non-combustible material. (c) underline("Chittsmack") does not burn by itself. (d) Some substances on combustion produce underline("thea") and underline("mafel.") (e) The amount of heat energy produced on complete combustion of 1 kg of a fuel is called its underline("ficalroic") value.

A surface of area 1 m^(2) kept perpendicular to the sun rays absorbs 3 MJ solar energy in one hour. (a) What is the amount of solar energy absorbed by a solar heater when a surface of area of 9 cm^(2) is exposed perpendicular to the sun rays for 4 hours. (b) What is amount of time taken by this heater to boil 12 kg of water at 40^(@)C if its efficiency is 60% ? specific heat capacity of water =4200 J kg^(-1) .^(@)C^(-1)

In a petrol engine, the rate of production of heat due to combustion of the fuel is 5xx10^(6) cal h^(-1) . The efficiency of the engine is 30%. Calculate the H.P. of the engine. Given, J=4.2 J cal^(-1) and 1 h.p. =746 W.