Question

Which is an example of radiation?

Troy’s hand is burned when he touches hot wax.
Earth is heated by energy from the Sun.
A hot dog is held over a fire and gets warm.
Water is boiled in a pot on a stove burner.

Answer 1

Earth is heated by energy from the Sun.

Explanation: Radiation is heat transfer by electromagnetic waves, which can travel through the vacuum of space — sunlight warming Earth is a direct example. (A hot dog over a fire also receives heat by radiation, but it’s also warmed by convection from hot air; touching hot wax is conduction, and boiling water on a burner involves conduction into the pot and convection in the water.)