What happens to the energy of visible light as it moves from red to violet?

• A. The energy increases.
• B. The speed decreases.
• C. The wavelength increases.
• D. The frequency decreases.

Answer: (A)

As visible light transitions from red to violet, the energy of the light actually increases. This increase in energy is due to the relationship defined by Planck’s equation, which relates the energy of a photon to its frequency (E = hf, where E is energy, h is Planck's constant, and f is frequency).

In the visible spectrum, red light has the longest wavelength and lowest frequency, while violet light has a shorter wavelength and higher frequency. Since frequency is directly proportional to energy, as the frequency increases from red to violet, the energy of the photons also increases.

This understanding of the relationship between wavelength, frequency, and energy is fundamental in the study of light and its properties, reflecting why the answer is unequivocally that energy increases as light moves from red to violet.