When monochromatic light falls on a photo sensitive metal, an electron is emitted with maximum velocity $1.6 \times 10^6 \mathrm{~m} / \mathrm{s}$. Find the stopping potential.

[charge of electron $=1.6 \times 10^{-19} \mathrm{C}$, mass of electron $\left.=9 \times 10^{-31} \mathrm{~kg}\right]$

A lamp of power 942 W radiates energy uniformly in all direction. The wavelength of radiation is 660 nm .The photon flux on a small screen 5.0 m from the lamp in units of photon $/ \mathrm{m}^2 \mathrm{~s} Q$ is

(take Planck's constant, $h=6.6 \times 10^{-34}$ SI unit)

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 a metal surface is called the work function of the metal.

Which of the following is correct?

Which of the following has the largest de-Broglie wavelength?