A 4-watt night light is left on for 8 hours each night. How much work dies it do per night

The light bulb doesn't do any "work" ... it doesn't exert force,

or maintain a force through a distance. It does, however,

dissipate energy, in the form of heat and light.

The quantity of energy that it dissipates is ...

(4 watts) x (8 hours) x (3600 sec/hour) x (1 joule/watt-sec)

= (4 x 8 x 3600) joules = 115,200 joules.