Monochromatic light of frequency `6 xx 10^(14) Hz ` is produced by a LASER .the power emitted is `2 xx 10^(-3)W`.The number of phtotons smitted,on the average ,by the source per second is

Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. The power emitted is 9.42 mW. How many photons per second, on the average, arrive at a target irradiated by this beam? (Assume the beam to have uniform cross-section which is less than the taget area).

Light of frequency 7.21 x 10^(14)Hz (Hertz) is incident on a metal surface. Electrons with a maximum speed if 6.0 xx 10^5ms^(-1) (metre per second) are ejected from the surface. What is the threshold frequency fro photo emission of electrons? Given rarr h(Planck constant) = 6.63 xx 10^(-34) Js (Joule Second) m_e (mass of electron)= 9.1 xx 10^(-31) kg (kilogram)

Electromagnetic waves of frequency 5 xx 10^(14) Hz are passed through a liquid.The wavelength of the waves in liquid is measured to be 4.5 xx 10^(-7) m . Calculate the wavelength of e.m. waves in vacuum,

The work function of caesium metal is 2.14 eV. When light of frequency 6 xx 10^14 Hz is incident on the metal surface, photomission of electrons occurs. What is the maximum speed of the emitted photoelectrons?

Find the wavelength of electromagnetic waves of frequency 6 xx 10^12 Hz in free space. Give its two applications.