$A$ beam of photons with an energy of $10.5 \ eV$ strikes a metal plate. The photoelectrons are emitted with a maximum velocity of $1.6 \times 10^6 \ m \ s^{-1}$. The work function of the metal is (Assume mass of electron $= 9 \times 10^{-31} \ kg$ and charge of electron $= 1.6 \times 10^{-19} \ C$). (in $eV$)

$A$ photon of energy $8 \ eV$ is incident on a metal surface of threshold frequency $1.6 \times 10^{15} \ Hz$. The maximum kinetic energy of the photoelectrons emitted (in $eV$) is: (Take $h = 6 \times 10^{-34} \ J \cdot s$ and $1 \ eV = 1.6 \times 10^{-19} \ J$)

When ultraviolet radiation of a certain frequency falls on a potassium target,the photoelectrons released can be stopped completely by a retarding potential of $0.6 \, V$. If the frequency of the radiation is increased by $10 \%$,this stopping potential rises to $0.9 \, V$. The work function of potassium is ........ $eV$.

Electrons ejected from the surface of a metal,when light of a certain frequency is incident on it,are stopped fully by a retarding potential of $3 \ V$. The photoelectric effect on this metallic surface begins at a frequency of $6 \times 10^{14} \ s^{-1}$. The frequency of the incident light in $s^{-1}$ is: [Planck's constant $= 6.4 \times 10^{-34} \ J \cdot s$,charge on the electron $= 1.6 \times 10^{-19} \ C$]

$A$ photon of wavelength $3315 \ \text{Å}$ falls on a photocathode and an electron of energy $3 \times 10^{-19} \ \text{J}$ is ejected. The threshold wavelength of the photon is [Planck's constant $(h)$ $= 6.63 \times 10^{-34} \ \text{J-s}$, velocity of light $(c)$ $= 3 \times 10^{8} \ \text{m/s}$]. (in $\text{Å}$)

When monochromatic light falls on a photo-sensitive metal,an electron is emitted with maximum velocity $1.6 \times 10^6 \ m/s$. Find the stopping potential.
[charge of electron $= 1.6 \times 10^{-19} \ C$,mass of electron $= 9 \times 10^{-31} \ kg$] (in $V$)