A flashlight converts chemical energy into light energy.
A joule is roughly the energy used by a flashlight turned on for one second.
Flashlights use joules.
What is converted in a flashlight?

[1] hydrogen and oxygen
[2] adding heat
[3] an electron lens
[4] hydrogen to water
[5] chemicals to light
[6] batteries into solar
[7] heat into light
[8] chlorofluorocarbons