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 \(15~\text{m}^2\), 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)
(3) Between 0 and
(4) Equal to that of an electron
The energy of a photon is E = hv and the momentum of photon , then the velocity of photon will be
(1) E/p
(2) Ep
(3)
(4)
The energy of a quanta of frequency Hz and will be:
1.
2.
3.
4.
Wavelength of a 1 keV photon is . What is the frequency of 1 MeV photon?
1.
2.
3.
4.
What is the momentum of a photon having frequency ?
(a) (b)
(c) (d)
Which of the following is true for photon
(1)
(2)
(3)
(4)
The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100W is (taking h = J-sec)
(a) 100 (b) 1000
(c) (d)