The gas which is supplied to the heating system in a flat has 400 kJ of chemical potential energy.  Of this, 320 kJ is transferred to the thermal store of the fluid inside the radiators in the flat.  Calculate the efficiency of the heating system.

(e)     When the heater is supplied with 120 J of energy each second, the internal energy of theice increases by 45 J each second.Use the following equation to calculate the efficiency of the heater.

A boiler delivers 5400kg of steam per hour at a pressure of 800kN/m2 and with a drynessfraction of 0.98. The feedwater to the boiler is at a temperature of 42oC. The fuel usedfor the boiler has a calorific value of 31000kJ/kg.(i) Determine the heat energy absorbed by the steam per hour in the boiler

A heat engine with an efficiency of 25% takes 1400 J of heat from the high temperature heat source and does J of work in each cycle.

A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.Calculate the overall efficiency of the electric car.Hint: First work out the useful output energy. You do not need to convert from kilojoules (kJ) to joules (J).

7.Question 7A rigid container holds an ideal gas with c_v = 0.75 kJ/(kgK). The container is cooled from 110 ℃ to 20 ℃. Find the specific heat transfer (kJ/kg) for the process. 1 point-96 kJ/kg96 kJ/kg67.5 kJ/kg-67.5 kJ/kg