SSC Scientific Assistant - General Physics 1000+ MCQ [Solved] PDF Download

1. The scientist who first sent electromagnetic waves to distant places was
A. James Clerk Maxwell
B. Heinrich Hertz
C. Thomas Alva Edison
D. Baird
Answer : C

2. The speed of sound in a medium depends upon the properties of the medium such as
A. its density
B. its temperature
C. its elasticity
D. All the above
Answer : D

3. The attraction of unlike molecules at the common surface is known as
A. adhesion
B. cohesion
C. surface tension
D. capillarity
Answer : A

4. Pieces of camphor placed on water move about rapidly. This is because of
A. diffusion
B. viscosity
C. surface tension
D. capillarity
Answer : C

5. X-rays were discovered by
A. Wilhelm Roentgen
B. WO Coolidge
C. Henry Cavendish
D. William Watson
Answer : A

6. A device used in a ship for the purpose of measuring the depth of the sea is
A. an altimeter
B. a fathometer
C. a hydrometer
D. a sonometer
Answer : B

7. The pressure of air at high altitude is less than the atmospheric pressure at the sea level. Hence the boning point of water at a hill top
A. is more than at sea level
B. is equal to that sea level
C. is less than at sea level
D. depends on the surrounding temperature
Answer : C

8. The number of galaxies that are visible without telescope on clear dark nights and away from bright lights is
A. one
B. two
C. three
D. infinite
Answer : C

9. A permanent magnet may be demagnetised by
A. placing it inside a solenoid through which an alternating current is flowing
B. heating the magnet to redness and then allowing it to cool
C. dropping it several times or hammering it while lying east-west
D. All the above
Answer : D

10. The maximum displacement of the particle in a mechanical wave motion is known as
A. amplitude
B. vibration
C. frequency
D. phase
Answer : A

11. The tiniest of the stars belong to the group known as
A. Giant stars
B. White Dwarf stars
C. Neutron stars
D. Super-giant stars
Answer : C

12. Who first established the fact that the earth revolves round the sun?
A. Sir Isaac Newton
B. Kepler
C. Copernicus
D. Ptolemy
Answer : C

13. The instrument used to measure atmospheric pressure is
A. Pyrometer
B. Eudiometer
C. Barometer
D. Hydrometer
Answer : C

14. The velocity required to place a vehicle in orbit round the moon is _________ that required to place it in orbit round the earth.
A. less than
B. greater than
C. equal to
D. greater than or equal to
Answer : A

15. The air inside an electric, bulb is removed to prevent
A. oxidation of the tungsten filament
B. bursting of the bulb
C. loss of light due to absorption
D. keeping the weight of the bulb less
Answer : A

16. The strength of an electromagnet can be increased by
A. increasing the length of the coiled wire
B. increasing current supply
C. increasing the size of the iron core
D. All the above
Answer : D

17. The mirage is a phenomenon
A. generally considered as a desert happening
B. caused by unequal heating of the several layers of the atmosphere above the desert
C. in which the refracted rays take a curved path resulting in total internal refection
D. All the above
Answer : D

18. In an electrical circuit, a fuse is connected
A. in the live wire
B. in the neutral wire
C. in the earth wire
D. anywhere
Answer : A

19. A man Jumping out of a moving train is thrown
A. forward
B. backward
C. sideways
D. None of the above
Answer : A

20. An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consists or
A. sugar
B. sodium carbonate
C. common salt
D. carbonates of calcium and magnesium
Answer : D

21. A workman was working on a rail track. A young boy at a distance holds his ear close to the railway track. The boy was able to hear the sound of each blow or the workman twice. It is because
A. speed of sound is greater in steel than in air
B. speed of sound is greater in air than in steel
C. part of sound waves is reflected between rail tracks
D. the boy's ears are at a different distance from the source
Answer : A

22. Besides protons, the nucleus of an atom contains
A. electrons
B. neutrons
C. neutrons and electrons
D. electrons, neutrons and other particles
Answer : B

23. When an electric apparatus is fitted with a three core flexible lead the insulation on the three wires is distinctively coloured. The present international convention is
A. brown for earth, yellow for live, light blue for neutral
B. green for earth, yellow for live, brown for neutral
C. yellow for earth, green for live, brown for neutral
D. brown or red for live, light blue or black for neutral and green or yellow for earth
Answer : D

24. The planet that is known as earth's twin is
A. Mercury
B. Venus
C. Moon
D. Mars
Answer : B

25. Hydrophone is an instrument used
A. for measuring relative density of liquids
B. by ships to pass on messages
C. for determining the depth of ocean bottoms etc.
D. by deaf people to aid hearing
Answer : C

26. Which of the following is fissionable?
A. U-234
B. U-235
C. U-238
D. Both (b) and (c)
Answer : B

27. In experiments on static electricity the standard method for obtaining small amounts of positive electricity is to rub
A. a glass rod with flannel
B. an abonite rod with flannel
C. a glass rod with silk
D. Any of the above
Answer : C

28. A solid ball of metal has a spherical cavity inside it. When the ball is heated the volume of the cavity will
A. increase
B. decrease
C. remain unaffected
D. have its shape changed
Answer : A

29. Which of the following pairs is not correct?
A. Television - Baird
B. Transistor ~ Shockley
C. Thermometer - Celsius
D. Barometer Torricelli
Answer : C

30. Electron-volt is a unit of
A. power
B. velocity
C. energy widely used in nuclear physics
D. number of electrons
Answer : C

31. The freezer in a refrigerator is placed near the top
A. to keep it away from the hot compressor which is near the bottom
B. because of convenience
C. so that it can cool the whole interior by setting up convection currents
D. to prevent too much cooling
Answer : C

32. A hunter on the ground wishes to shoot a bird on a tree at a distance with his rifle. He has to point the rifle
A. at the lower elevation than the bird
B. at a higher elevation than the bird
C. in the same direction as the bird
D. vertically upwards
Answer : B

33. A radio set that uses valves does not start operating immediately when it is switched on whereas a set containing only tranaistors operates immediately. The reason for this is that
A. the valve filaments have low resistance
B. valve-radio sets work at a higher voltage
C. transistor set has a low resistance
D. filaments of the valves cake time to beat up and function
Answer : D

34. A bullet is fired at a certain angle with the horizontal. Its path will be
A. elliptical
B. a straight line
C. a parabola
D. a vertical line
Answer : C

35. A capillary tube is partially dipped vertically in a vessel containing water. Due to capillarity water rises in the tube. The height of water rise in the tube can be increased by
A. decreasing the radius of the capillary tube
B. increasing the radius of the capillary tube
C. increasing the height of water in the vessel
D. None of these
Answer : A

36. Cosmic rays are
A. powerful X-rays falling on the earth from space
B. ultraviolet rays from the sun
C. gamma rays from radioactive minerals
D. very energetic radiation falling upon the earth from outer space consisting chiefly of charged particles
Answer : D

37. The period of a geostationary (synchronous) satellite orbiting the earth over the equator la
A. 16 hours
B. 12 hours
C. 20 hours
D. 24 hours
Answer : D

38. When one enters a dark room after being in bright light one is not able to see anything clearly for a while because
A. the retina of the eye moves forward
B. the retina of the eye moves backward
C. c).the iris is unable to dilate the pupil immediately to be able to see things
D. the eye has no power of accommodation
Answer : C

39. When a bullet is fired from a gun
A. the gun moves forward
B. the gun jumps up
C. the gun does not move
D. the gun recoils with the same momentum as the bullet
Answer : D

40. The speed of light is minimum while passing through
A. air
B. glass
C. vacuum
D. water
Answer : B

41. A pressure gauge for fluids is called
A. a hydrometer
B. a manometer
C. a lactometer
D. an anemometer
Answer : B

42. A heavenly body similar in nature to the sun intensely hot glowing mass that produces its energy by thermonuclear reactions is
A. a planet
B. a meteor
C. a star
D. a comet
Answer : C

43. Photo-electric cells convert
A. electrical energy into light energy
B. light energy into electrical energy
C. light energy into heat energy
D. electrical energy into heat energy
Answer : B

44. Bats flying in the dark avoid obstacles because
A. they can see very dearly only in darkness
B. they produce ultrasonic waves which guide them
C. their eyes are sensitive to darkness
D. their eye holes expand in darkness
Answer : B

45. The velocity of sound in a medium is
A. directly proportional to its pressure
B. inversely proportional to the square root of its pressure
C. directly proportional to the square root of its pressure
D. independent of its pressure
Answer : D

46. If you want to open a door with les difficulty you push it
A. at the middle
B. at a point away from the hinge (near the rim)
C. near the hinge
D. None of the above
Answer : B

47. Tap water is placed in an open pad and allowed to evaporate. After some time the temperature of water
A. increases to a great extent
B. increases slightly
C. decreases slightly
D. decreases rapidly
Answer : C

48. For an electron orbiting in a hydrogen atom, the necessary centripetal force keeping it in orbit is provided by
A. the electrical attraction between the negatively charged electron and the positively charged porton
B. the high speed of the electron
C. the low speed of the electron
D. gravity
Answer : A

49. A stationary elevated object has
A. kinetic energy
B. potential energy
C. momentum
D. both potential and kinetic energy
Answer : B

50. A bolometer is used to measure
A. the quantity of heat energy in a body
B. thermal radiations quantitatively
C. high temperature
D. the intensity of sound
Answer : B