1. A step index fiber has a numerical aperture of 0.26, core refractive index
of 1.5 and a core diameter of 100µm Calculate the refractive of cladding.
2. A photon and an electron both have a wavelength of 1.00 nm. What are
the energy of photon and the kinetic energy of an electron?
3. What may be the photon energy for an electromagnetic wave with a
wavelength equal to the Compton wavelength of (a) the electron and (b)
the proton?
4. The wavelength of the yellow spectral emission line of sodium is 590
nm. At what kinetic energy would an electron have that wavelength as
its de Broglie wavelength?
5. X rays of wavelength 0.1 nm are scattered at such an angle that the
recoil electron has the maximum kinetic energy. Calculate the
wavelength of the scattered ray and the energy of the recoil electron.
6. Give the prompt reason behind the existence of population inversion in
metastable state during the lasing actions.
7. A monochromatic x ray beam with wavelength 50
scattered through 60º. Find wavelength of scattered beam.
pm
is
8. Justify the existence of population inversion in metastable state during
the lasing actions.
9. What parameters restrict classical mechanics to justify the
observations of Compton Effect?
10. Light travelling in air enters a sample of a liquid at an angle of
incidence of 35º.If the angle of refraction is 22.5º, what is the refractive
index of the liquid?
11. The intensity of sound in a street during heavy traffic is 10-6 W/m2.
Calculate the intensity level in dB.
12. Calculate the intensity level of a plane just leaving the runway having
sound intensity about 1000 W/m2.
13. Define intensity of sound. Give its unit. Define intensity level. Give the
physical significance of 1 dB.
14. What will be the maximum kinetic energy of electrons ejected from a
certain material with work function 2.3 eV when the light of frequency
3× 1015 Hz is incident on it?
15. An optical fiber core and its cladding have refractive index of 1.69 and
1.65 respectively. Calculate the critical angle, acceptance angle and
numerical aperture.
16. A hall of volume 1000m3 has a sound absorbing surface of area 400
m2. If the average absorption coefficient of the hall is 0.2 Sabine, what
will be the reverberation time of the hall?
17. The sound from drill gives a noise level of 95 dB at a point a few meters
away from it. What will be noise level at this point when four such drills
are working at the same distance away?
18. A graded index fiber has a core diameter of 0.05 mm and numerical
aperture of 0.22 at a wavelength of 8500 angstrom. What is the number
of modes guided in core?
19. If the work function of target material is 1.24 eV and the wavelength
of incident light is 436 nm then calculate the velocity of a photoelectron.
What retarding potential is necessary to stop emission of such
electrons?
20. What will be the Larmor radius for a 5 keV electron in the Earth’s
magnetic field of 0.37 Gauss and solar wind proton having a velocity of
300 km/sec in a magnetic field of 4 x 10-5 gauss.