Encyclopedia of Solved Past Papers

# PPSC Physics Subject Specialist & Senior Subject Specialist Solved Past Papers

## PPSC Physics Subject Specialist & Senior Subject Specialist Solved Past Papers

1. A portable device which is widely used for the detection of ionizing particle or radiations:
(a) Geiger counter ✓
(b) Wilson cloud chamber
(c) Solid state dector
(d) None of these

02. 1 Kwh=
(a) 6×10^2 Joule
(b) 6×10^5 Joule
(c) 6×10^6 Joule
(d) 36×10^5 Joule ✓

03. The essential part/s of a moving coil galvanometer is/are:
(I) A U-Shaped permanent magnet with cylindrical concave pole-pieces (II) A flat coil of thin enamel insulated wire usually rectangular (II) An spiral metallic wire connected to external terminal
(a) I only
(b) I & II only ✓
(c) I, II & III
(d) II & III

04. Calculate the centripetal acceleration and centripetal force on a man whose mass is 80 kg when resting on the ground at the equator if the radius of earth is 6.4×10^6 m.
(a) 69 N
(b) 35 N
(c) 69 N ✓
(d) 65 N

05. The process of combining audio frequency (a-f) and radio frequency (r-f) waves to accomplish translational is called:
(a) Transmission
(b) Rectifier
(c) Modulation ✓
(d) Crystal Diode

06. A convex lens of focal length 20 cm, is used to form an erect image which is twice as long as the object. Find the position of the object?
(a) 10 cm ✓
(b) 20 cm
(c) -20 cm
(d) 5 cm

07. The electron acquires a speed of 10^6 ms^-1. Find its energy in electron volts:
(a) 66 ev
(b) 84 ev ✓
(c) 23 ev
(d) 34 ev

08. A basic electric instrument which is used for the detection (or measurement) of small current:
(a) Ammeter
(b) Voltmeter
(c) Galvanometer ✓
(d) Transmitter

09.ΔV/ΔS is the rate of change of potential with respect to the distance and it is called:
(a) Electric field
(b) Electric flux
(c) Potential Difference
(d) Potential Gradient ✓

The resonant frequency of an LC-Circuit is:
(a) f = 2Π LC
(b) f = 1 / 2Π√ LC
(c) f = 1/ 2LC
(d) None of these

10. Which one of the following is NOT needed in Nuclear Fission reactor?
(a) fuel
(b) accelerator
(c) moderator
(d) None of these

11. A Watt – sec is a unit of:
(a) Force
(b) Energy
(c) Power
(d) None of these

12. The force on a charge moving with the velocity in a magnetic field B is given by:
(a) F = (q/v x B)
(b) F = ( qv x B )
(c) F = (qv + B)
(d) None of these

13. The half life of a radioactive isotope is 140 days. How many days would it take to loose 3/4 of its Initial activities:
(a) 105 days
(b) 280 days
(c) 35 days
(d) None of these

14. A U-235 nucleus will split when it captures:
(a) an α-particle
(b) m. radiation
(c) neutron
(d) None of these

15. An LRC Circuit has R= 4Ω, Xc = 3 and XL=6, the impedance of the circuit is:
(a) 5 Ω
(b) 7 Ω
(c) 13 Ω
(d) None of these

16. A magnetic field cannot:
(a) Accelerate a charge
(b) Exert a force on a charge
(c) Change the kinetic energy of a charge
(d) None of these

17.For hydrogen atom the energy needed to ionize it is____________ electron volts and the corresponding ionization potential is____________.
(a) 6 volts, 6 volts
(b) 12 volts, 12.6 volts
(c) 6 volts, 13 volts
(d) 6 volts, 13.6 volts ✓

18.The length of a measuring rod is 1 m when it is at rest. What will its length be if it is moving with a velocity one third of the speed of light.
(a) 943 m ✓
(b) 346 m
(c) 64 m
(d) 563 m

19.A changing current “i” in any circuit induces an emf “e” in that circuit, which is equal to:
(a) e = di/dt
(b) E = i dΦ/dt
(c) e = – L di/dt
(d) None of these

20.The resonant frequency of an LC-Circuit is:
(a) f = 2Π LC
(b) f = 1 / 2Π√ LC
(c) f = 1/ 2LC
(d) None of these

21. The induced current always flows in such a direction as to oppose the change which is giving rise to it, This state of:
(a) Ampere’s law
(b) Ohm’s law
(c) Newton’s law
(d) Lenz’s law ✓

22. A neutron travels a distance of 12 m in a time interval of 3.6×10^-4 s. Assuming its speed was constant, find its kinetic energy. Take 1.7×10^-27 kg as the mass of neutron.
(a) 87 ev
(b) 78 ev ✓
(c) 56 ev
(d) -8.56 ev

23. The energy stored in the fossil fuel is
(a) chemical energy ✓
(b) heat energy
(c) Electrical energy
(d) Elastic potential energy

24. Electrochemical energy is required for the working of
(a) Circulatory system
(b) Nervous system ✓
(c) Excretory system
(d) Digestive system

25. A vector has a magnitude of 12. When its tail is at the origin it lies between the positive x axis and the negative y axis and makes an angle of 30◦ with the x axis. Its y component is:
(a) 6/√3
(b) −6√3
(c) 6
(d) −6 ✓

26. The hydraulic automobile jack illustrates:
(a) Archimedes’ principle
(b) Pascal’s principle ✓
(c) Hooke’s law
(d) Newton’s third law

27. What is the magnifying power of a convex lens of focal length 5 cm?
(a) 3
(b) 5
(c) 6 ✓
(d) 20

28. Which portion of light has a wavelength in a range from 400 to 780 nm, with a frequency range of 405 to 790 Hz?
(a) infrared light
(b) visible light ✓
(c) ultra-violet light
(d) none of the above

29. Candela is a unit of
(a) acoustic intensity
(b) electric intensity
(c) luminous intensity ✓
(d) magnetic intensity

30. Which are different types of emission spectrum?
(a) continuous spectrum
(b) line spectrum
(c) band spectrum
(d) all of the above ✓

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