A light source emits monochromatic light of wavelength 555 nm. The source consumes 100 W of electric power and emits 35 W of radiant flux. Calculate the overall luminous efficiency.

The luminous flux of a monochromatic source of 1 w is 450 lumen. Find the relative luminosity at the wavelength emitted.

A source emits light of wavelengths 555 nm and 600 nm. The radiant flux of the 555 nm part is 40 W and of the 600 nm part is 30 W. The relative luminosity at 600 nm is 06. Find (A) the total radiant flux, (B) the total luminous flux, (C) the luminous efficiency.

A source emits 314 W of a radiant flux distributed uniformly in all directions. The luminous efficiency is 60 lumen . What is the luminous intensity of the source?

A point source emitting 628 lumen of luminous flux uniformly in all directions is placed at the origin. Calculated the illuminance on a small area placed at (10 m, 0, 0) in such a way that the normal to the area makes an angle of 37° with the X-axis.