PUNJAB PUBLIC SERVICE COMMISSION
COMBINED COMPETITIVE EXAMINATION FOR
RECRUITMENT TO THE POSTS OF
PROVINCIAL MANAGEMENT SERVICE-2019
SUBJECT: PHYSICS (PAPER – II)
TIME ALLOWED: THREE HOURS MAXIMUM MARKS: 100
NOTE: Attempt Five Questions in All and TWO each from Section-II and III. Calculator is allowed (Not Programmable). Attempt in Urdu or English. Selecting ONE from Section – I
SECTION – I
Q No. 1: (a) Define Compton Effect. Derive an expression for Compton Shift in wavelength.
(b) If the wavelength of incident X-rays is 1.5 A, calculate the frequency of X-rays scattered at an angle of 60° in Compton Scattering. Where h = 6.63 x 10-34 J.s, m = 9.11 x 10-31 Kg, c = 3 x 108 m/s (12 + 8 = 20 Marks)
Q No. 2: (a) State Maxwell’s equation in words and through appropriate differential and integral forms.
(b) Use Ampere’s law to show that the magnitude of the magnetic field inside an infinitely long solenoid, with “n” turns of wire per unit length and current “I” passing through it, is given by B = μ0nI
(c) Calculate the voltage of a battery connected to a parallel plate capacitor with a plate area of 2.0 cm2 and a plate separation of 2.0 mm if the charge stored on the plates is 4.0 pC. (8 + 8 + 4 = 20 Marks)
SECTION-II
Q No. 3: (a) What is the Law of Radioactivity. Derive an expression for mean life of radioactive element by using this law.
(b) How much percent radioactive atoms of a radioactive substance will left after three mean lives. (12 + 8 = 20 Marks)
Q No. 4: (a) Write a note on working of an operational amplifier.
(b) Discuss the operation of J-K flip flops. (10 + 10 = 20 Marks)
Q No. 5: (a) What is diode? Explain the working of full wave rectifier.
(b) Define transistor (BJT). Explain cutoff, saturation, and active region. (10 + 10 = 20 Marks)
SECTION-III
Q No. 6: (a) Write a brief note on nuclear models.
(b) Define nuclear fission and fusion. What is role of moderation in nuclear reactor?
(c) Indium-115 has a half-life equal to 4.5 hours. If the sample were Originally 12 mg how much would remain after 13.5 hours? (12 + 4 + 4 = 20 Marks)
Q No. 7: Write a note on the following: (4 x 5 = 20 Marks)
(a) Zeeman Effect (b) Pair production (c) Heisenberg’s Uncertainty Principle (d) Quantum Numbers
Q No. 8: (a) Write a note on Mass spectrometer.
(b) Differentiate between Poisson and Laplace’s Equation
(c) Monochromatic light of wavelength λ = 400 nm strikes a plate of Cesium. Cesium has a work function of 2.14 eV. What is the energy of the electrons ejected? (10 + 6 + 4 = 20 Marks)