CBSE Class 12 Physics Question Paper 2008 (Outside Delhi)

CBSE CLASS XII Questions

• 1.

  The resistance of a metal wire at \( 20^\circ \text{C} \) is \( 1.05 \, \Omega \) and at \( 100^\circ \text{C} \) is \( 1.38 \, \Omega \). Determine the temperature coefficient of resistivity of this metal.

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• 2.

  Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.
  

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• 3.

  Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?
  

  • The total charge of the two spheres is conserved.
    
  • Both spheres attain the same potential.
    
  • The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2)}{(r_1 + r_2)}$
    
  • The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2) (r_1 + r_2)}{r_1 r_2}$
    
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• 4.

  Read the following paragraph and answer the questions that follow.
  In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves the lens away from the object towards the screen and finds that she is able to form sharp image of the object for two positions of the lens. The distance between these two positions of the lens is d.
  

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• 5.

  Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

  • \( (M_x - M_z)<M_y \)
    
  • \( (M_x - M_y)<M_z \)
    
  • \( M_x>(M_y + M_z) \)
    
  • \( M_x<(M_y + M_z) \)
    
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• 6.

  An astronomical telescope consists of two converging lenses. One of them of large aperture and large focal length is called objective lens and the other one, of smaller focal length and smaller aperture is called the eyepiece. It is used to see distant objects which are not seen clearly with naked eyes. The image formed by the objective lens acts as an object for the eyepiece and the final image produced by the eyepiece is magnified.