A radiation of energy 'E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (c=velocity of light)

1. E/c

2. 2E/c

3. 2E/c²

4. E/c²

Light with an energy flux of \(25\times 10^{4}~\text{Wm}^{-2}\) falls on a perfectly reflecting surface at normal incidence. If the surface area is \(15~\text{cm}^2\), then the average force exerted on the surface is:
1. \(1.25\times 10^{-6}~\text{N}\)
2. \(2.5\times 10^{-6}~\text{N}\)
3. \(1.2\times 10^{-6}~\text{N}\)
4. \(3.0\times 10^{-6}~\text{N}\)

Particle nature and wave nature of electromagnetic waves and electrons can be shown by 

(1) Electron has small mass, deflected by the metal sheet

(2) X-ray is diffracted, reflected by thick metal sheet

(3) Light is refracted and defracted

(4) Photoelectricity and electron microscopy

The rest mass of the photon is

(1) 0

(2)$\infty$

(3) Between 0 and $\infty$

(4) Equal to that of an electron

The energy of a photon is E = hv and the momentum of photon $\mathrm{p}=\frac{\mathrm{h}}{\mathrm{\lambda }}$, then the velocity of photon will be

(1) E/p                     

(2) Ep

(3)  ${\left(\frac{\mathrm{E}}{\mathrm{P}}\right)}^2$                 

(4) $3\times {10}^8<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$

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

1. $1.24\times {10}^{15}<mspace\; width="1em"></mspace>\mathrm{Hz}$      
2.  $2.4\times {10}^{20}<mspace\; width="1em"></mspace>\mathrm{Hz}$
3. $1.24\times {10}^{18}<mspace\; width="1em"></mspace>\mathrm{Hz}$      
4. $2.4\times {10}^{23}<mspace\; width="1em"></mspace>\mathrm{Hz}$

What is the momentum of a photon having frequency $1.5\times {10}^{13}<mspace\; width="1em"></mspace>\mathrm{Hz}$?
(a) $3.3\times {10}^{-29}<mspace\; width="1em"></mspace>\mathrm{kg}<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$                (b) $3.3\times {10}^{-34}<mspace\; width="1em"></mspace>\mathrm{kg}<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$
(c) $6.6\times {10}^{-34}<mspace\; width="1em"></mspace>\mathrm{kg}<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$                (d) $6.6\times {10}^{-30}<mspace\; width="1em"></mspace>\mathrm{kg}<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$

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

The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100W is (taking h = $6\times {10}^{-34}<mspace\; width="1em"></mspace>$J-sec)

(a) 100                 (b) 1000
(c) $3\times {10}^{20}$           (d) $3\times {10}^{18}$