A light with a single wavelength is called which term?

A light with a single wavelength is called which term?

• A. Coherent Light
• B. Plume
• C. Pump
• D. Monochromatic Light

Answer: (D)

Monochromatic light means light that contains only one wavelength, so its spectrum is a single color. Most real sources emit a range of wavelengths, but when that range is essentially a single wavelength, the beam is considered monochromatic. Coherent light refers to a fixed phase relationship between waves, which can occur with monochromatic light but isn’t required for it to be monochromatic. The other terms don’t describe wavelength content: a plume isn’t a light-property term, and a pump is the energy source used to excite a medium in devices like lasers, not a description of the light’s color or wavelength.

Monochromatic light means light that contains only one wavelength, so its spectrum is a single color. Most real sources emit a range of wavelengths, but when that range is essentially a single wavelength, the beam is considered monochromatic. Coherent light refers to a fixed phase relationship between waves, which can occur with monochromatic light but isn’t required for it to be monochromatic. The other terms don’t describe wavelength content: a plume isn’t a light-property term, and a pump is the energy source used to excite a medium in devices like lasers, not a description of the light’s color or wavelength.