# 100 Physics Questions and Answers – Basic Physics

**Physics Questions – Learn Basic Physics Part 1 (1-25)**

1) Who invented the spinning cup anemometer?

Answer: Thomas Romney Robinson (1846).

2) The minimum amount of energy required to remove the most loosely bonded electron is called as?

Answer: Ionisation energy.

3) Who was the first person to design models of flying machine?

Answer: Leonardo da Vinci.

4) Of the following quantities, which one has dimension different from the remaining three?

(a) Energy per unit volume (b) Force per unit area (c) Product of voltage and charge per unit volume (d) Angular momentum.

Answer: D.

5)Who tried to prove that air is weightless?

Answer: Voltaire.

6) When does the value of energy become zero for an electron?

Answer: Far away from the nucleus.

7) Who invented Aqua-Lung?

Answer: Jacques Cousteau (1943).

8) In a vernier caliper N divisions of vernier scale coincides with (N – 1) divisions of main scale (in which length of one division is 1 mm). The least count of the instrument should be

(a) N (b) N – 1 (c) 1/10 N (d) 1/N – 1

Answer: C.

9) Aqua-Lung is used by:

Answer: Divers.

10) The vacant space of a solid’s, electronic energy level is _

Answer: Hole.

11) Who invented Archimedean screw?

Answer: Archimedes.

12) In a particular system, the unit of length, mass and time are chosen to be 10 cm, 10 g and 0.1 s respectively. The unit of force in this system will be equivalent to

(a) 0.1 N (b) 1 N (c) 10 N (d) 100 N

Answer: A.

13) How long did it take for Henry Ford to assemble a Model Tear after establishing conveyer belt?

Answer: 93 minutes.

14) A petrol engine used to mix petrol and air in a certain ratio for combustion, is called _

Answer: Carburettor.

15) What does astrolabe determine?

Answer: It determines the altitude of an object in the sky eg: Sun & Stars.

16) Which of the following is a dimensional constant?

(a) Refractive index (b) Poissons ratio (c) Relative density (d) Gravitational constant

Answer: D.

17) Astrolabe is now replaced by:

Answer: Sextant.

18) What is the potential energy of an electron when it is far away from the nucleus?

Answer: Zero.

19) When was sextant invented?

Answer: Both England & America in 1731.

20) The percentage of errors in the measurement of mass and speed are 2% and 3% respectively. The error in kinetic energy obtained by measuring mass and speed will be

(a) 12% (b) 10% (c) 8% (d) 2%

Answer: C.

21)Who invented the sewing machine?

Answer: Barthélemy Thimonnier (1830).

22) The book Hydrodynamic containing the explanation of Bernoulli’s theorem was published by whom in the year 1738?

Answer: Daniel Bernoulli.

23) Who invented the Smoke alarm?

Answer: BRK electronics (1967).

24) The density of a cube is measured by measuring its mass and length of its sides. If the maximum error in the measurement of mass and length are 4% and 3% respectively, the maximum error in the measurement of density will

(a) 7% (b) 9% (c) 12% (d) 13%

Answer: D.

25) Who invented the microwave?

Answer: Percy Spencer.

## Online Physics Questions and Answers – Basic Physics Part 2 (26-50)

26) What is the energy equivalent of the mass of an electron?

Answer: Mass of an electron = 0.0511 eV.

27) What happens to its frequency, when the tension of a string increases?

Answer: Its vibration will increase.

28) Which one of the following groups have quantities that do not have the same dimensions?

(a) pressure, stress (b) velocity, speed (c) force, impulse (d) work, energy

Answer: C.

29) What is called the frequency of a sound when it is more than 20000 Hz?

Answer: Ultrasonic sound.

30) Name the scientist who first proposed the wave theory of light?

Answer: Christian Huygens.

31) What is the unit of frequency?

Answer: Cycle/ sec.

32) The dimensions of Planck’s constant are same as

(a) energy (b) power (c) momentum (d) angular momentum

Answer: D.

33) What are sound waves?

Answer: Longitudinal waves.

34) Acceleration due to gravity measured in Gal is equal to _

Answer: 1 cm/s2.

35) What is called a wave motion in which the particles of the medium vibrate parallel to the direction of propagation of wave?

Answer: Longitudinal.

36) The ratio of the dimension of Planck’s constant and that of the moment of inertia is the dimension of

(a) time (b) frequency (c) angular momentum (d) velocity

Answer: B.

37) How is the sound produced when we speak?

Answer: By the vibration of vocal cords.

38) A barn of nuclei is equal to _

Answer: 10-24 cm2.

39) Which sound is produced by Galton whistle?

Answer: Ultrasonic.

40) If the error in the measurement of radius of a sphere is 2%, then the error in the determination of volume of the sphere will be:

(a) 4% (b) 6% (c) 8% (d) 2%

Answer: B.

41) How is sound produced when a harmonium is played?

Answer: By the vibration of the reeds.

42) Magnetic flux density is measured in _

Answer: Tesla.

43) What is required for the propagation of sound?

Answer: Some medium.

44) Which two of the following five physical parameters have the same dimensions? (A) Energy density (B) Refractive index (C) Dielectric constant (D) Young’s modulus (E) Magnetic field

(a) (B) and (D) (b) (C) and (E) (c) (A) and (D) (d) (A) and (E)

Answer: C.

45) Write an example of a transverse wave:

Answer: Lightwave.

46) How is the mass of an electron get converted to energy?

Answer: Combining it with a positron.

47) When the frequency of the sound wave is increased, what happens to its wavelength?

Answer: Decreases.

48) The density of material in CGS system of units is 4g/cm3. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of the material will be

(a) 0.4 (b) 40 (c) 400 (d) 0.04

Answer: B.

49) Which unit is used to measure the frequency of sound?

Answer: Hertz.

50) What is the term used to refer the exchange of energy between a particle and an electromagnetic wave?

Answer: Radiation heat.

51) How is sound produced?

Answer: By the vibration of material objects.

## General Physics Questions and Answers – Learn Basic Physics Part 3 (51-75)

52) The pair of quantities having the same dimensions is

(a) Young’s modulus and energy (b) impulse and surface tension (c) angular momentum and work (d) work and torque

Answer: D.

53) How is sound produced in a flute?

Answer: By the vibration of the air colum.

54) The unit of Viscosity in the CGS system is _

Answer: Poise.

55) What is the formula for velocity?

Answer: Velocity = frequency x wavelength.

56) A train of 150 meters long is going towards north direction at a speed of 10 m/s. A parrot flies at the speed of 5 m/s towards south direction parallel to the railway track. The time taken by the parrot to cross the train is

(a) 12 sec (b) 8 sec (c) 15 sec (d) 10 sec

Answer: D.

57) What is known as the maximum displacement of the particles of the medium from their equilibrium position?

Answer: Amplitude.

58) Around the nucleus, surrounds the electron with a total energy _

Answer: Less than zero.

59) How is echo produced?

Answer: By the reflection of sound.

60) What will be the ratio of the distances moved by a freely falling body from rest in 4th and 5th seconds of the journey?

(a) 4: 5 (b) 7: 9 (c) 16: 25 (d) 1: 1

Answer: B.

61) What is called a wave in which particles of the medium vibrate perpendicular to the direction of propagation of the wave?

Answer: Transverse wave.

62) 1022J of energy can be related equal to which among the following?

Answer: Solar energy received per day on the earth.

63) How is the speed of the supersonic plane expressed?

Answer: Mach numbers.

64) A car covers the first half of the distance between two places at 40 km/h and other half at 60 km/h. The average speed of the car is

(a) 40 km/h (b) 48 km/h (c) 50 km/h (d) 60 km/h

Answer: B.

65) What is mean by the distance between two successive points in the medium where the particles are in the same phase of vibration?

Answer: Wavelength.

66) What is the reciprocal of the impedance of an electric current?

Answer: Admittance.

67) When will the sound be painful to the ears?

Answer: When the sound is above 120 dB).

68) A bus traveling the first one-third distance at a speed of 10 km/h, the next one third at 20 km/h and the last one-third at 60 km/h. The average speed of the bus is

(a) 9 km/h (b) 16 km/h (c) 18 km/h (d) 48 km/h 6. A car moves a distance of 200 m. It covers

Answer: C.

69)What is a sound?

Answer: Sound is a form of energy which produces the sensation of hearing.

70) Why is 8th November 1895 regarded as a special day of physics?

Answer: W. Roentgen discovered X-rays.

71) What are the essential characteristics of a wave?

Answer: Wavelength, amplitude, frequency, and velocity.

72) A car moves a distance of 200 m. It covers the first half of the distance at speed 40 km/h and the second half of distance at speed v. The average speed is 48 km/h. Find the value of v

(a) 56 km/h (b) 60 km/h (c) 50 km/h (d) 48 km/h

Answer: B.

73) What is frequency?

Answer: The number of vibrations made by a body in one second is called its frequency.

74) The unit ‘Nit’ is used in what?

Answer: Luminance.

75) What do you mean by audio frequency?

Answer: Audio frequency is the frequency of audio sound.

## Top Physics Questions and Answers – Learn the Basics of Physics Part 4 (76-100)

76) A body is thrown vertically upward from the ground. It reaches a maximum height of 20 min 5 sec. After what time, it will reach the ground from its maximum height position?

(a) 2.5 sec (b) 5 sec (c) 10 sec (d) 25 sec

Answer: B.

77) What is the practical unit of loudness?

Answer: Decibel (dB).

78) Among the following, the unit of sound absorption is _

Answer: Sabin.

79) What are the elements required for the sensation of hearing?

Answer: A vibrating source, a propagating medium, and a receiver namely ear.

80) If a car at rest accelerates uniformly to a speed of 144 km/h in 20 s, it covers a distance of

(a) 2880 m (b) 1440 m (c) 400 m (d) 20 m

Answer: C.

81) What is supersonic?

Answer: Supersonic refers to the speed of an object moving with a speed greater than that of sound.

82) 2 December 1942 is known for:

Answer: The creation of the first controlled chain reaction.

83) What are the essential characteristics of a musical sound?

Answer: Loudness, pitch, and quality are the characteristics of a musical sound.

84) A car moving with a speed of 40 km/h can be stopped by applying brakes at least after 2 m. If the same car is moving with a speed of 80 km/h, what is the minimum stopping distance?

(a) 8 m (b) 6 m (c) 4 m (d) 2 m

Answer: A.

85) What is known as the study of sound?

Answer: Acoustics.

86) The Standard Unit of measurement of magnetic field strength is _

Answer: Ampère per meter.

87) What is the distance between a compression and its nearest rarefaction in a longitudinal wave?

Answer: L/2.

88) Two bodies, A (of mass 1 kg) and B (of mass 3 kg), are dropped from heights of 16m and 25m, respectively. The ratio of the time taken by them to reach the ground is

(a) 12/5 (b) 5/12 (c) 4/5 (d) 5/4

Answer: C.

89) How will you show by experiment that there is a transfer of energy by the wave?

Answer: We place a cork on water and then throw a stone on water near the cork.

90) An engine develops 10 kW of power. How much time will it take to lift a mass of 200 kg to a height of 40 meters (g = 10 ms2)

Answer: 8 sec.

91) Why is sound heard more intense in carbon dioxide in comparison to air?

Answer: The intensity of sound increases with increase in the density of the medium.

92) A man of 50 kg mass is standing in a gravity-free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed 2 m/s. When the stone reaches the floor, the distance of the man above the floor will be:

(a) 9.9 m (b) 10.1 m (c) 10 m (d) 20 m

Answer: B.

93) A wave is expressed by the equation, Y=0.5 sin 71 (0.01 x-3t), where y and x are in meter and t in seconds. Find the speed of propagation?

Answer: V – 300 m/sec.

94) What is called the energy, which an electron acquires when accelerated through a potential difference of 1 volt?

Answer: 1 e v.

95) Which property of sound is affected by a change in air temperature?

Answer: Wavelength.

96) A bus is moving on a straight road towards the north with a uniform speed of 50 km/hour turns through 90°. If the speed remains unchanged after turning, the increase in the velocity of the bus in the turning process is

(a) 70.7 km/hour along south-west direction (b) zero (c) 50 km/hour along west (d) 70.7 km/hour along north-west direction.

Answer: A.

97) Which property of a wave is independent of the other?

Answer: Amplitude.

98) What is called the perpendicular distance from the effort to fulcrum?

Answer: Effort arm.

99) Where can transverse waves propagate?

Answer: Not in a gas but in a metal.

100) When milk is churned, the cream gets separated due to

(a) centripetal force (b) centrifugal force (c) frictional force (d) gravitational force

Answer: B.

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