PHYSICS

DUAL NATURE OF MATTER AND RADIATION 1. With what purpose was famous Davisson-Gerber experiment with electrons performed? 2. How will the photoelectric current change on decreasing the wavelength of incident radiation for a given photosensitive material? 3. Name the experiment which establishes the wave nature of a particle? 4. How does the ‘ stopping potential ‘in photoelectric emission depend upon (i) the intensity of the incident radiation (ii)the frequency of the incident radiation? 5. Show graphically how the stopping potential for a given photosensitive surface varies with the frequency of the incident radiation.  6. If the intensity of the incident radiation on a photosensitive surface is doubled, how does the kinetic energy of the emitted electrons get affected? 7. Define work function for a given metallic surface?.Prove that the de-Broglie wavelength λ of electrons of energy E is given by, λ =h/ √ 2mE 8. Two beams, one of red light and the other of

GRAVITATION 1.        State and explain Newton’s law of gravitation. Hence define Gravitational Constant G. What is its value in SI? 2.        Define acceleration due to gravity. Discuss the variation of acceleration due to gravity with-i) the altitude ii) the depth and iii) the shape of the earth. 3.        Discuss the variation of acceleration due to gravity due to rotation of earth. What is the effect on g at poles and equator of the earth due to rotation of earth? 4.        Derive the relation                                      g = GM/R 2  for acceleration due to gravity of the earth,where M and R are the mass and radius of the earth. 5.        Show that the acceleration of free fall g at the surface of earth and the gravitational constant G are related by the expression                          g = 4/3 πρ GR, where ρ is mean density of the earth and R, radius of the earth. 6.        State and explain Kepler’s laws of planetary motion. 7.        State Kepler