Answer:
Step-by-step explanation:
The correct answer is: E = hc, where E is the energy, h is the Planck constant, and c is the speed of light. This equation is known as the Planck-Einstein equation, which relates the energy of a photon (a particle of light) to its frequency. This equation is a fundamental principle in physics and is central to many areas of modern physics, including quantum mechanics, thermodynamics, and statistical mechanics. It is also used in various practical applications, such as in the calculation of energy levels in atoms and molecules.