Question

A __________ is the amount of light given off by a light source from a certain angle that is perceived by the human eye.

Answer 1

Lumen.

Step-by-step explanation:

Lumen may be defined as the S.I. unit of the luminous flux and denoted by the ln. The human eye can only see the wavelength of the lights lies in the visible spectrum.

The power of light perceived by the eye is known as Luminous flux . One lumen may be defined as the amount of luminous flux emitted from a directional unit point source through the unit solid angle.

Thus, the lumen is the correct answer.

Answer 2

Lumen

Step-by-step explanation:

Luminous flux is known as the power of light perceived by the eye. The SI unit of luminous flux is known as lumen where one lumen is the amount of luminous flux emitted from a directional unit point source through a unit solid angle.

Since the human eye can see only the visible spectrum of light which is perceived in the form of luminous flux and thus lumen.

Thus, the lumen is the correct answer.