PHYSICS EXAM
1Mark 1X10 =10
1. Atomic spectrum should be
(a) pure line spectrum (b) emission band spectrum
(c) absorption line spectrum (d) absorption band spectrum.
2. When a drop of water is introduced between the glass plate and
plano convex lens in Newton’s rings system, the ring system
(a) contracts (b) expands
(c) remains same (d) first expands, then contracts
3 A beam of monochromatic light enters from vacuum into a medium
of refractive index μ. The ratio of the wavelengths of the incident
and refracted waves is
(a) μ : 1 (b) 1 : μ
(c) μ2 : 1 (d) 1 : μ2
4. If the wavelength of the light is reduced to one fourth, then the
amount of scattering is
(a) increased by 16 times (b) decreased by 16 times
(c) increased by 256 times (d) decreased by 256 times
5. In Newton’s ring experiment the radii of the mth and (m + 4)th dark
rings are respectively 5 mm and 7 mm. What is the value of m?
(a) 2 (b) 4
(c) 8 (d) 10
6. A narrow electron beam passes undeviated through an electric
field E = 3 × 104 V/m and an overlapping magnetic field
B = 2×10−3 Wb/m2. The electron motion, electric field and magnetic
field are mutually perpendicular. The speed of the electron is
(a) 60 ms−1 (b) 10.3 × 107 ms−1
(c) 1.5 × 107 ms−1 (d) 0.67 × 10−7 ms−1
7. According to Bohr’s postulates, which of the following quantities
take discrete values?
(a) kinetic energy (b) potential energy
(c) angular momentum (d) momentum
8. The ratio of the radii of the first three Bohr orbit is,
(a) 1 : 1/2 : 1/3 (b) 1 : 2 : 3
(c) 1 : 4 : 9 (d) 1 : 8 : 27
9. The first excitation potential energy or the minimum energy required
to excite the atom from ground state of hydrogen atom is,
(a) 13.6 eV (b) 10.2eV
(c) 3.4 eV (d) 1.89 eV
10. According to Rutherford atom model, the spectral lines emitted by
an atom is,
(a) line spectrum (b) continuous spectrum
(c) continuous absorption specturm (d) band spectrum
3 Mark 3 X10 =30
1.Write any three uses of infrared radiations.
2.what are emission and absorption spectra?
3.What is band emission spectrum?Give an example.
4.What is tyndall scattering?
5.Why does sky appear blue in color?
6.State Huygens principle?
7.State and Brewster’s law.
8.why is the centre of newton’s ring dark?
9.Define specific rotation?
10. In Newton’s rings experiment the diameter of certain order of
dark ring is measured to be double that of second ring. What is
the order of the ring?
11.state mosley’s law. Write its equation
12.write any three applications of laser.
13Calculate the longest wavelength that can be analysed by a rock
salt crystal of spacing d = 2.82Å in the first order.
14.Explain any one of the drawbacks of the reutherford atom model.
15.State postulates of Bohr atom model?
5Mark
5 X 6 =30
1.Write any 5 properties of cathode rays.
2.Explain the spectral series of hydrogen atom.
3. In Bragg’s spectrometer, the glancing angle for first order
spectrum was observed to be 8o. Calculate the wavelength of
X-ray, if d = 2.82 × 10−10 m. At what angle will the second
maximum occur?
4.State and obtain Bragg’s Law.
5.State and prove Brewster,s law.
6.Write a note on Nicol prism.
7.Appicaton of polaroids.
8. A soap film of refractive index 1.33, is illuminated by white light
incident at an angle 30o. The reflected light is examined by
spectroscope in which dark band corresponding to the wavelength
6000Å is found. Calculate the smallest thickness of the film.
10 Mark.
10X3 =30
1.What is Raman scattering ? Explain raman scattering with energy level diagram.
2.what is known as interference of light? Derive an expression for bandwidth of interference fringes in young’s
double slit experiment.
3.Dscribe the J.J Thomson method of determining the specific charge of an electron.
4.Draw a neat sketch of ruby laser.Explain the working with the help of energy level diagram.