HSC Physics- 1st Paper (Theo) Model Question-2

HSC Physics- 1^st Paper (Theo) Model Question for Class- XII

1.   a.   Explain the scalar and vector products of two vectors, with necessary diagram.                              5

      b.   Show that the trajectory of a projectile is parabolic.                                                                          6

      c.   A bullet after penetrating 3cm of a wall loses half of its speed. How far will the bullet penetrate the wall afterwards?                                                                                                                             4

Or,

1. State Newton’s third law of motion. Prove the principle of conservation of momentum from this law.           5
2. Prove that   a =                                                                                                                              6
3. A force of magnitude 30N acts on a body at rest and of mass 6kg. After 10s what will be its kinetic energy.                                                                                                                                                            4

2.   a.   What is called mean free path? Derive an expression for mean free path.                                         5

      b.   Prove that  C_p – C_v = R.                                                                                                                      6

      c.   A fixed amount of gas at 27⁰ C is suddenly expanded to double its original volume. What is the final temperature? ( g = 1.4 )                                                                                                                       4

Or,

a . State and explain Stefan’s law and from this law describe how Newton’s law of cooling can be derived?                                                                                                                                     5

     b.    Describe a method for determining latent heat of fusion of ice.                                                        6

     c.    5 Kg of ice at -10⁰ C is mixed with 20 g of water at  40⁰ C. What will be the final temperature of the

mixture?                                                                                                                                              4

3.   a.  Distinguish between transverse and longitudinal wave.                                                                     5

      b.   Derive the general equation of a progressive wave.                                                                           6

      c.   The frequency of a stationary wave in a medium is 320 Hz. The distance between two successive

nodes of the wave is 0.52m. Find the speed of the wave.                                                                 4

Or,

1. What is called resonance, free and forced vibration?                                                 2 + 1.5 +1.5 = 5
2. State and explain the laws of transverse vibration of a stretched string.                                           6
3. The string of a sonometer is in resonance with a tuning fork of frequency 200 Hz. If the length

of the string is increased by 1%, How many beats will be heard?                                                     4

4.         Prove the principle of conservation of mechanical energy in case of a simple pendulum.                 5

Or,      

Describe Cavendish method to determine ‘G’.

5.         Determine the differential equation of a simple harmonic motion and find its general solution.      5

Or,      

Define elastic potential energy. Show that the elastic potential energy per unit volume of a

body =                                                                                                                   5

6.         Describe the experiment to determine the surface tension of water by capillary rise method.          5

Or,      

What is angle of contact? A large drop is formed by 25 small drops of water, each of diameters

0.17×10^-2 m. Find the energy released. (Surface tension of water = 72 × 10^-3 Nm^-1.)

7.         What is called ideal black body? A metallic sphere of radius 0.3 m radiates 25 W powers. Find the temperature of the sphere. ( σ = 5.67 ×10^-8 Wm^-2 K^-4 )                                                                  5

Or,      

State and explain Second law of thermodynamics. Prove that η =  .                                    2+3 =   5

8.         Describe the construction and working principle of a thermoelectric thermometer.                          5

Or,      

State with figure Wien’s law. Explain Green house effect.                                                               5

9.         State and explain Newton’s law for the velocity of sound. Why and how Laplace made correction

of Newton’s law?                                                                                                                               5

Or,      

Derive an expression for the apparent frequency of sound when a source is moving towards the stationary observer.                                                                                                                                  5

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