Physics XII

 

                        CANTT PUBLIC HIGH SCHOOL & BOYS COLLEGE

                  WAHDAT COLONY TAXILA   

 

Sessional Exams 02         2021

 

Name: _______________________________________

Class: XII                    Paper: Physics                    Time:  20   Minutes                    Marks: (1✕10 = 10)

 

SECTION –A

 

Note: Section-A is compulsory. Deleting and overwriting is not allowed. Do not use lead pencil.

Q1.Encircle the correct options i.e. A, B, C, D. All parts carry equal marks.

 

        i.            Compton’s Effect was presented by

A.        Mosely             B.        Marely             C.        Arthur Holly     D.        All

      ii.            The types of quarks are

A.   4                           B.        4                      C.        6                      D.        5

  iii.            γ- emission from the nucleus of an atom causes a change in

A.        Z                      B.        A                     C.        A & Z              D.        None

4. A wire is stretched to double of its length, its strain will be

A.        2                      B.        1                      C.        0                      D.        0.5

      v.            The bands below the valence band are normally

 A.       Empty              B. Partially Filled          C. Completely Filled     D.        Absent

    vi.            For rectification we use

A.        Transformer      B.        Diode               C.        Choke             D.        Generator

  vii.             In full wave rectification, number of diodes required are equal to

A.        4                      B.        3                      C.        5                      D.        1

viii.            Albert Einstein was awarded Nobel Prize, in physics in

A.        1916                B.        1918                C.        1921                D.        1923

9. Which is not a characteristics of LASER

 A. Monochromatic      B.        Coherent          C.        Intense             D.        Multi Directional

10. Which particle is positively charged

A.        Alpha               B.        Beta                 C.        Gamma            D.        Photon

 

 

 

For Examiner’s Use Only                                                                      Q.No.1 Total Marks:

                                                                                                            Marks Obtained:

 

 

 

 

Class: XII                          Paper: Physics                          Time:  2 h 10 Minutes                      Marks: 40

 

Section – B (Marks 12)

 

Q.2 Attempt any FOUR parts from the following. All parts carry equal marks.                (4x3=12)

        i.            Discuss the superconductivity of a conductor with the help of a curve.

      ii.            What do you mean by conduction band?

    iii.            Explain why the base current is weak as compare to collector current?              

    iv.            Why the emitter base junction is forward biased and collector base junction is reversed biased?

      v.            Why transistor is called current amplification device?

    vi.            All objects radiate energy. Explain why, then, are we not able to see objects in a dark room.

 

Section - C (Marks 12)

 

Q.3 Attempt any FOUR parts from the following. All parts carry equal marks.                (4x3=12)

     i.                  What happens to total radiation from black body if its absolute temperature is doubled?

   ii.                  Explain why it is impossible for a particle to move faster than the speed of light?

 iii.                  X-Rays can emit electrons from metal surface and X-rays can be diffracted. Comment?                      

 iv.                  What are laser knives?

   v.                  What is color force?

 vi.               Element X has several isotopes. What do these isotopes have in common? How do they differ?

Section - D (Marks 16)

Note: Attempt any TWO questions.                                                                                     (8x2=16)

Q4.      (a) Explain the flow of AC through an inductor.                                                             (4)

             (b) Briefly explain Energy band Theory.                                                                        (4)

Q5.       (a) Define Transistor. Also explain common emitter configuration.                                 (4)

             (b) What do you mean by Photo Electric Effect? Explain                                               (4)

Q6.       (a) Write a note on LASER.                                                                                        (4)

             (b) What are the building blocks of matter? Explain                                                       (4)

 

**GOOD - LUCK **