Question

Which of the following devices does not convert heat energy to mechanical energy?

internal combustion engine

coal-fueled power plant

steam turbine

windmill
I think its the coal fueled power plant?

Answer 1

@ybarrap

Answer 2

An internal COMBUSTION engine means something explodes, therefore there is heat
coal-FUELED power plant means something is burnt
STEAM turbine implies water is boiled to make steam and to be boiled it must be heated

That leaves only one option that does NOT convert heat energy into mechanical energy. In fact it converts mechanical energy into electromagnetic energy.