The light of two different frequencies whose photons have energies $3.8 \,eV$ and $1.4 \,eV$ respectively, illuminate a metallic surface whose work function is $0.6 \,eV$ successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectivly will be

A $100 \;W$ sodium lamp radiates energy uniformly in all directions. The lamp is located at the centre of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\; nm$.

$(a)$ What is the energy per photon associated with the sodium light?

$(b)$ At what rate are the photons delivered to the sphere?

Given below are two statements

Statement$-I :$ Two photons having equal linear momenta have equal wavelengths.

Statement$-II :$ If the wavelength of photon is decreased, then the momentum and energy of a photon will also decrease.

In the light of the above statements, choose the correct answer from the options given below.

Consider figure for photoemission.

How would you reconcile with momentum-conservation ? Note light (photons) have momentum in a different direction than the emitted electrons. 

A source $S_1$ is producing, $10^{15}$ photons per second of wavelength $5000 \;\mathring A.$ Another source $S_2$ is producing $1.02 \times 10^{15}$ photons per second of wavelength $5100\;\mathring A$. Then, $($ power of $S_2)/$  $($ power of $S_1)$ is equal to

Assertion : The photoelectrons produced by a monochromatic light beam incident on a metal surface, have a spread in their kinetic energies.
Reason : The work function of the metal varies as a function of depth from the surface.