All of them.
An electromagnetic wave, or electromagnetic radiation.
"Visible light"
Light contains energy in the form of the photons of electromagnetic radiation
Light is an electromagnetic wave. All electromagnetic waves are a form of energy. This question can be viewed from the quantum theory angle. Light would thus consist of photons with energies proportional to the frequency of the light.
Energy -- usually in the form of light (or more generally, electromagnetic radiation).
What form of energy emission accompanies the return of excited electrons to the ground state?
max plank
Light is a form of electromagnetic energy.
For a long time, scientists thought that gravity might be an extremely long waved form of electromagnetic energy. Since then, scientists found that all forms of electromagnetic energy travel in little bundles called photons and they have established that these photons have mass and they have also established that gravity has no mass so it is not a form of electromagnetic energy.
Electromagnetic waves (or particles, if you wish). These can be photons (light), x-rays and other similar waves.
The energy travels through space in the form of electromagnetic radiation, which can be described as a plane wave motion or alternatively as a stream of photons.
Photons. (In the form of electromagnetic radiation)