Question

?Lumen? is the unit of

• A. Luminous flux
• B. Luminous intensity
• C. illuminance
• D. Light frequency

Answer 1

Answer: (A)

Luminous flux

Answer 2

The lumen is the SI derived unit of luminous flux, a measured of the total quantity of visible light emitted by a source per unit time.
where,
$1$ lumen ($1$m ) $= 1\,\, Cd/Sr$
$\because \,Cd =$ candela and $Sr =$ steradians