The work functions of Caesium $(Cs)$,Potassium $(K)$ and Sodium $(Na)$ are $2.14\,eV,2.30\,eV$ and $2.75\,eV$ respectively. If incident electromagnetic radiation has an incident energy of $2.20\, eV$, which of these photosensitive surfaces may emit photoelectrons?

The momentum of a photon in an $X-$ ray beam of ${10^{ - 10}}$ metre wavelength is

Monochromatic light of frequency $6.0 \times 10^{14}\,\, Hz$ is produced by a laser. The power emitted is $2 \times 10^{-3}\,\, W.$ The number of photons emitted, on the average, by the source per second is

An electron and a photon have same wavelength of $10^{-9} \,m$. If $E$ is the energy of the photon and $p$ is the momentum of the electron, then the magnitude of $E / p$ (in $SI$ unit) is

In photo electric effect

$A.$ The photocurrent is proportional to the intensity of the incident radiation.

$B.$ Maximum Kinetic energy with which photoelectrons are emitted depends on the intensity of incident light.

$C.$ Max. $K.E$ with which photoelectrons are emitted depends on the frequency of incident light.

$D.$ The emission of photoelectrons require a minimum threshold intensity of incident radiation.

$E.$ Max. K.E of the photoelectrons is independent of the frequency of the incident light.

Choose the correct answer from the options given below:

If $2.5 \times 10^{-6\,} N$ average force is exerted by a light wave on a non-reflecting surface of $30\, cm ^{2}$ area during $40$ minutes of time span, the energy flux of light just before it falls on the surface is .................. $W / cm ^{2}$

(Round off to the Nearest Integer)

(Assume complete absorption and normal incidence conditions are there)