Physics CSS Paper II 2020
FEDERAL PUBLIC SERVICE COMMISSION
COMPETITIVE EXAMINATION – 2020
FOR RECRUITMENT TO POST IN BS – 17
UNDER THE FEDERAL GOVERNMENT
PHYSICS, PAPER II
TIME ALLOWED: THREE HOURS
PART – I (MCQs): MAXIMUM 30 MINUTES
PART – I (MCQs): MAXIMUM MARKS = 20
PART – II MAXIMUM MARKS = 80
NOTE:
(i) Part – II is to be attempted on the separate Answer Book.
(ii) Attempt ONLY FOUR questions from PART – II. ALL questions carry EQUAL marks.
(iii) All the parts (if any) of each Question must be attempted at one place instead of at different places.
(iv) Candidate must write Q. No. in the Answer Book in Accordance with Q. No. in the Q. Paper.
(v) No Page / Space be left blank between the answers. All the blank pages of Answer Book must be crossed.
(iv) Extra attempt of any question or any part of the attempted question will not be considered.
PART II
Q. 2. (a) Discuss electric field of point charges, keeping in view the magnitude of force acting on test charge according to Coulomb’s Law. (8)
(b) Derive Poisson’s equation from Gauss’s Law. Also write the expression for Laplace’s equation. (8)
(c) Find out the electric field due to charge of 2e at a distance of 26.5 x 10-12 m. (Em – 8.85 x 10-12 C2 / N.m2 and e-1 60 x 10 -1 C) (4) (20)
Q. 3. (a) Discuss in details the Energy Transport and the Poynting Vector. (8)
(b) Write the Maxwell’s Equations both in integral and differential forms. (8)
(c) Explain vector potential. (4) (20)
Q. 4. (a) State and explain Heisenberg’s Uncertainty Principle. (8)
(b) Discuss the phenomenon Barrie Tunneling. (8)
(c) Find the momentum of an electron moving with a speed of 1.88 x 106 m/s, where mass of electron is 9.11 x 10-31 kg. (4) (20)
Q. 5. (a) What do you understand by the term Dopping? How we can make semiconductors as n-type or p-type with the dopping? (8)
(b) Discuss in details the N-P-N and P-N-P transistors. (8)
(c) Explain MOFET. (4) (20)
Q. 6. (a) Discuss in detail the process of Natural Radioactivity. (8)
(b) Discuss in detail the radioactive decay. (8)
(c) Find the energy released during the alpha-decay of 238 U. Where the needed atomic masses are 235U 238.050785 u, 234Th 234.044549 u and 4He 4.002603 u. (4) (20)
Q. 7. (a) Discuss in detail the phenomenon of Fission. (8)
(b) Explain the basic principles of Nuclear Reactors. (8)
(c) Briefly write about the methods of detection of nuclear radiation. (4) (20)
Q. 8. Write notes on any TWO of the following: (10 each) (20)
(a) Dielectric medium and Electric Polarization
(b) Ampere’s Law
(c) Accelerators
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