In a photoelectric effect experiment,three different metal plates $p, q,$ and $r$ have work functions $\phi_p = 2.0 \ eV, \phi_q = 2.5 \ eV,$ and $\phi_r = 3.0 \ eV$. The incident light beams have wavelengths $\lambda_p = 550 \ nm, \lambda_q = 450 \ nm,$ and $\lambda_r = 350 \ nm$. The intensity of light is the same for each plate. The correct $I-V$ graph for the experiment is: $[hc = 1240 \ eV \ nm]$

Dual nature of light is exhibited by

Find the number of photons emitted per second by a $25 \text{ W}$ source of monochromatic light of wavelength $6600 \text{ Å}$. What is the photoelectric current assuming $3 \%$ efficiency for the photoelectric effect?

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

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 $= 9 \times 10^{-31} \ kg$).

Statement $(I)$ : By increasing the potential difference between cathode and anode continuously in a photoelectric experiment,the photocurrent always increases continuously.
Statement $(II)$ : If two photons $A$ and $B$ of energies $2.5 \ eV$ and $3.5 \ eV$ respectively fall on a metal surface of work function $2.0 \ eV$,then the ratio of maximum kinetic energies emitted between $A$ and $B$ is $3$.
Statement $(III)$ : The maximum energy needed by an electron to come out from metal surface is called the work function of the metal.
Which of the following is correct?