PUNJAB PUBLIC SERVICE COMMISSION

COMBINED COMPETITIVE EXAMINATION

FOR RECRUITMENT TO THE POSTS OF

PROVINCIAL MANAGEMENT SERVICE, ETC

FOR RECRUITMENT TO THE POSTS OF

PROVINCIAL MANAGEMENT SERVICE, ETC

__PHYSICS (OPTIONAL) PAPER-II__

TIME ALLOWED: 3 HOURS MAXIMUM MARKS: 100

Note: Attempt in English language.

Attempt any FIVE questions only, selecting at least ONE from each Section.

SECTION-I

What do you mean by electric flux? State and prove Gaus's Law, hence calculate the electric field due to infinite sheet of charge. (12)

Two large metal plates of area 1.0m

^{2}face each other. They are 5.0cm apart and have equal but opposite charges on their inner surfaces. If the magnitude E of electric field between the two plates is 55 N/c, what is the magnitude of charge on each plate? Neglect edge effect. (8)Q.2: (a) What is alternating current and its basic advantage. Discuss RLC circuit.

(b) An oscillating LC circuit consisting of a 1.0 nF capacitor and a 3.0 mH coil has maximum voltage of 3.0V. (i) What is maximum charge on the capacitor? (ii) what is the maximum current through circuit? (8)

SECTION-II

Q.3: (a) What is operational amplifier? Describe the use of an operational amplifier as an inverting amplifier. Find the expression for its gain. (12)

(b) The current flowing into the base of a transistor is 100MA, find the collector current lc, the emitter current Ir and the ratio 1c4E it the value of current gain 13 is 10. (8)

Q.4: (a) What do you mean by Octal numbers and Hexadecimal

numbers? Explain with example. What is BCD? (10)

(b) Convert each of the following Octal numbers to Binary. (6)

(i) I3 (ii) 25ri (iii) 140s

(c) Convert each of the following decimal numbers to BCD. (4) (i) 35 (ii) 98

SECTION-III

Q.5: (a) What is radioactivity? Discuss briefly cc, Band y decay. (12)

(b) In nuclear fission of U

^{235},^{}about 9% of the total energy liberated comes from 11-decay of fission product. How much power is carried away by neutrinos from a nuclear power plant which liberates heat at the rate of 100,000 kw? (8)Q.6: (a) Write few lines about quantum numbers. State and prove Paul's exclusive principle. (12)

(b) What is the de-broglie wavelength of (i) a hydrogen molecule moving at a speed of 2.4 x 10

^{,}cm/sec (ii) a rifle bulletweighing 2.0 gm and moving at a speed of 400 m/sec. (8)

Q.7: Write notes on any two of the following: (10, 10)

(i) Elementary particles and their properties

(ii) Poynting theorem and pointing vector

(iii) De I'vlorgan's theorems

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