Short Answer TypeA proton and an α-particle have the same de-Broglie wavelength. Determine the ratio of (i) their accelerating potentials (ii) their speeds.
Show that the radius of the orbit in hydrogen atom varies as , where n is the principal quantum number of the atom.
Use the mirror equation to show that an object placed between f and 2f of a concave mirror produces a real image beyond 2f?
Let us consider three polaroids A, B and C where C is kept in between A and B.
Using Malu’s Law, the intensity of light emerging from the middle polaroid C is given by,
Therefore, intensity falls on the polaroid at the end (polaroid B) whose polarisation axis makes an angle of ( 90° - θ ) with the polarisation axis of the angle of middle polaroid.
Therefore, Intensity of light emerging from Polaroid B is, 
That is, transmitted intensity will be maximum when sin 2 
= 1 
(i) A giant refracting telescope has an objective lens of focal length 15 m. If an eye piece of focal length 1.0 cm is used, what is the angular magnification of the telescope?
(ii) If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens ? The diameter of the moon is 3.48 × 106 m and the radius of lunar orbit is 3.8 × 108 m.Write Einstein’s photoelectric equation and mention which important features in photoelectric effect can be explained with the help of this equation. The maximum kinetic energy of the photoelectrons gets doubled when the wavelength of light incident on the surface changes from 
to 
. Derive the expressions for the threshold wavelength 
and work function for the metal surface.
In the study of Geiger-Marsdon experiment on scattering of α particles by a thin foil of gold, draw the trajectory of -particles in the coulomb field of target nucleus. Explain briefly how one gets the information on the size of the nucleus from this study. From the relation R = Ro A1/3 where Ro is constant and A is the mass number of the nucleus, show that nuclear matter density is independent of A.
Distinguish between nuclear fission and fusion. Show how in both these processes energy is released.
Calculate the energy release in MeV in the deuterium-tritium fusion reaction:
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