Question

what two forms of energy operate according to their wavelength and frequency?
a light and sound
b heat and light
c sound and heat
d none of the above

Explanation:

• Light: Light is an electromagnetic wave. The relationship between its speed (\(c\)), wavelength (\(\lambda\)) and frequency (\(f\)) is \(c = \lambda\times f\), where \(c\approx3\times 10^{8}\space m/s\) in vacuum.
• Sound: Sound is a mechanical wave. The speed of sound (\(v\)) in a medium is related to its wavelength (\(\lambda\)) and frequency (\(f\)) by the formula \(v=\lambda\times f\). For example, the speed of sound in air at room - temperature is approximately \(v = 340\space m/s\).
• Heat: Heat transfer mainly occurs through conduction, convection, and radiation. While thermal radiation is related to electromagnetic waves (and thus has wavelength and frequency characteristics for the radiative part), the concepts of wavelength and frequency are not the fundamental ways to describe the "operation" of heat in general (such as in conduction and convection). But since the question asks for two forms of energy and light (as a form of electromagnetic - wave - related energy) and sound (a mechanical - wave - related energy) are wave - based forms of energy described by wavelength and frequency.

Answer:

A. Light and sound