A light bulb is supplied with $100\mathrm{J}$ of energy every second.

How many joules of energy leave the bulb every second in the form of heat and light$?$

A light bulb is supplied with $100\mathrm{J}$ of energy each second.

If $10\mathrm{J}$ of energy leave the lamp each second in the form of light, how many joules leave each second in the form of heat$?$

Calculate the efficiency of the energy. efficient lamp from the data shown in 

A coal-fired power station produces $100\mathrm{MJ}$ of electrical energy when it is supplied with $400\mathrm{MJ}$ of energy from its fuel. Calculate its its efficiency.

A lamp of $10\%$ efficient, how much electrical energy must be supplied to the lamp each second if it produces $20\mathrm{J}$ of light energy per second$?$

The object's g.p.e. increasing, decreasing or remaining constant$?$ An apple falls from a tree. With example.