Question

The amount of light that falls per unit area held perpendicular to the rays in one second is called

• A. Candle power
• B. Dioptre
• C. Lumen
• D. Intensity of illumination

Answer 1

The correct option is D Intensity of illumination

Candle power- It is the rating of light output at source. It is the the candle's luminous intensity in a particular direction.

Dioptre- It is the ability of a lens to bend the light rays. A unit of power of lens.

Lumen- The amount of energy emanating from one square meter of surface.

Intensity of illumination - The amount of light falling on per unit area, held perpendicular to the rays in one second.