In a photocell,bichromatic light of wavelengths $2475 \ \mathring{A}$ and $6000 \ \mathring{A}$ is incident on a cathode whose work function is $4.8 \ eV$. If a uniform magnetic field of $3 \times 10^{-5} \ T$ exists parallel to the plate,the radius of the path described by the photoelectron will be ............ $cm$ (mass of electron $= 9 \times 10^{-31} \ kg$).

In the photoelectric effect:
$A.$ The photocurrent is proportional to the intensity of the incident radiation.
$B.$ The maximum kinetic energy with which photoelectrons are emitted depends on the intensity of incident light.
$C.$ The maximum kinetic energy with which photoelectrons are emitted depends on the frequency of incident light.
$D.$ The emission of photoelectrons requires a minimum threshold intensity of incident radiation.
$E.$ The maximum kinetic energy of the photoelectrons is independent of the frequency of the incident light.
Choose the correct answer from the options given below:

Given below are two statements:
Statement $I$: Out of microwaves,infrared rays,and ultraviolet rays,ultraviolet rays are the most effective for the emission of electrons from a metallic surface.
Statement $II$: Above the threshold frequency,the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light.
In the light of the above statements,choose the correct answer from the options given below:

Light of wavelength $2475 \, Å$ is incident on barium. Photoelectrons emitted describe a circle of radius $100 \, cm$ in a magnetic field of flux density $\frac{1}{\sqrt{17}} \times 10^{-5} \, T$. The work function of the barium is .............. $eV$ (Given $\frac{e}{m} = 1.7 \times 10^{11} \, C/kg$)

Name the device used for measuring the mass of atoms and molecules.

Assertion $(A)$: In the photoelectric effect,on increasing the intensity of light,both the number of electrons emitted and the kinetic energy of each of them increase,but the photoelectric current remains unchanged.
Reason $(R)$: The photoelectric current depends only on the wavelength of light.