What is the momentum of a photon in an \(X\text-\)ray beam of \(10^{-10}\) meter wavelength?

1.	\(1.5 \times 10^{-23}~\text{kg-m/s}\)
2.	\(6.6 \times 10^{-24}~\text{kg-m/s}\)
3.	\(6.6 \times 10^{-44}~\text{kg-m/s}\)
4.	\(2.2 \times 10^{-52}~\text{kg-m/s}\)

Wavelength of a 1 keV photon is $1.24\times {10}^{-9}m$. What is the frequency of 1 MeV photon?

1. $1.24\times {10}^{15} \mathrm{Hz}$      
2.  $2.4\times {10}^{20} \mathrm{Hz}$
3. $1.24\times {10}^{18} \mathrm{Hz}$      
4. $2.4\times {10}^{23} \mathrm{Hz}$

What is the momentum of a photon having frequency $1.5\times {10}^{13} \mathrm{Hz}$?
(a) $3.3\times {10}^{-29} \mathrm{kg} \mathrm{m}/\mathrm{s}$                (b) $3.3\times {10}^{-34} \mathrm{kg} \mathrm{m}/\mathrm{s}$
(c) $6.6\times {10}^{-34} \mathrm{kg} \mathrm{m}/\mathrm{s}$                (d) $6.6\times {10}^{-30} \mathrm{kg} \mathrm{m}/\mathrm{s}$

The energy of a photon of light of wavelength 450 nm is

(1) $4.4\times {10}^{-19} \mathrm{J}$             

(2) $2.5\times {10}^{-19} \mathrm{J}$

(3) $1.25\times {10}^{-17} \mathrm{J}$            

(4) $2.5\times {10}^{-17} \mathrm{J}$

Which of the following is true for photon 
(1) $\mathrm{E}=\frac{\mathrm{hc}}{\mathrm{\lambda }}$         

(2) $\mathrm{E}=\frac{1}{2}{\mathrm{mu}}^2$

(3) $\mathrm{p}=\frac{\mathrm{E}}{2\mathrm{v}}$         

(4) $\mathrm{E}=\frac{1}{2}{\mathrm{mc}}^2$

Einstein's photoelectric equation states that \(E_k=h \nu -\phi.\)${\mathrm{}}_{}$ In this equation \(E_k\) refers to:

Kinetic energy with which the electrons are emitted from the metal surface due to photoelectric effect is 

(1) Independent of the intensity of illumination

(2) Independent of the frequency of light

(3) Inversely proportional to the intensity of illumination

(4) Directly proportional to the intensity of illumination

The threshold wavelength for photoelectric emission from a material is 5200 Å. Photo-electrons will be emitted when this material is illuminated with monochromatic radiation from :

(1) 50-watt infrared lamp

(2) 50-watt ultraviolet lamp

(3) 1-watt ultraviolet lamp

(4) Both (2) and (3)

Threshold frequency for a metal is ${10}^{15}$ Hz. Light of $\mathrm{\lambda }=4000$$\stackrel{0}{\mathrm{A}}$ falls on its surface. Which of the following statements is correct

(1) No photoelectric emission takes place

(2) Photo-electrons come out with zero speed

(3) Photo-electrons come out with ${10}^3$ m/sec speed

(4) Photo-electrons come out with ${10}^5$ m/sec speed