(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 heat engine has an efficiency of 35.0% and receives 150 J of heat per cycle. How much work does it perform in each cycle?

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.

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.

The input power to machine is 18000W. Friction converts 1000J of energy into heat each second. What is the efficiency of the machine?Question 11Answera.100%b.94.74%c.94.44%d.5.56%

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).