The maximum kinetic energy of photoelectron emitted from the surface of work function f due to incidence of light of frequency n is E. If the frequency of incident light is doubled, then maximum kinetic of emitted photon will be

1.  2E

2.  2E - f

3.  2E + f

4.  2E + 2f

The de-Broglie associated with an electron accelerated through a voltage of 900 V is 

1.  $0.31 \stackrel{\mathrm{o}}{\mathrm{A}}$

2.  $0.41 \stackrel{\mathrm{o}}{\mathrm{A}}$

3.  $0.5 \stackrel{\mathrm{o}}{\mathrm{A}}$

4.  $0.16 \stackrel{0}{\mathrm{A}}$

$$\begin{gathered} \mathrm{A} 200\mathrm{W} \mathrm{sodium} \mathrm{street} \mathrm{lamp} \mathrm{emits} \mathrm{yellow} \mathrm{light} \mathrm{of} \mathrm{wavelength} 0.60\mathrm{\mu m}. \mathrm{Assuming} \mathrm{it} \mathrm{to} \mathrm{be} 50\% \mathrm{efficient}, \mathrm{in} \mathrm{converting} \\ \mathrm{electrical} \mathrm{energy} \mathrm{into} \mathrm{light}, \mathrm{the} \mathrm{number} \mathrm{of} \mathrm{photons} \mathrm{of} \mathrm{yellow} \mathrm{light} \mathrm{emitted} \mathrm{per} \mathrm{second} \mathrm{is} \mathrm{nearly} \mathrm{equal} \mathrm{to} \end{gathered}$$

1.  $3 x {10}^{19}$

2.  $3 x {10}^{20}$

3.  $1.5 x {10}^{20}$

4.  $6 x {10}^{20}$

Monochromatic radiation emitted when electron on hydrogen atom jumps from the first excited state to ground state irradiates a photosensitive material. The stopping potential is found to be 4V. The threshold wavelength of the material is 

1.  $2 \mathrm{x} {10}^{-7}\mathrm{m}$

2.  $2 \mathrm{x} {10}^{-6}\mathrm{m}$

3.  $4 \mathrm{x} {10}^{-7}\mathrm{m}$

4.  $4 \mathrm{x} {10}^{-6}\mathrm{m}$

In a photoelectric experiment using a metal of work function 1.8 eV, if the maximum kinetic energy of emitted electrons is 1.5eV, then the corresponding value to stopping potential is

1.  1.8V

2.  3.3V

3.  0.3V

4.  1.5V

The concept of matter-wave was given by

1.  de-Broglie

2.  Einstein

3.  Maxwell

4.  Bohr

If the momentum of a photon is p, then its energy is 

1.  pc

2.  $\frac{1}{2}\mathrm{pc}$

3.  $\frac{{\mathrm{p}}^2}{2\mathrm{c}}$

4.  $\frac{1}{4}\mathrm{pc}$