Calculate the wave number and frequency of a monochromatic radition of wavelength 400 nm?

Calculate the frequency of visible light of wavelength 650 nm.

Calculate the frequency and energy of a photon of wavelength 589 nm.

The number of photons emitted per second by a 60W source of monochromatic light of wavelength 663nm is

Calculate frequency of yellow radiation having wavelength 5800 overset@A

Maximum number of photons emitted by monochromatic light of wavelength 550 nm is ____ if 100 V and 1 A supplied for one hour.