Physics Questions Answers

• 29. Which instrument is used to measure pressure of gases ?

  1. Manometer
  2. Machmeter
  3. Magnetometer
  4. Micrometer

  Answer :

  Option A

  Explanation:

  Machmeter - is used to determine the speed of an aircraft in terms of speed of sound,
  
  Magnetometer - is used to compare magnetic movements and fields,
  
  Micrometer - is used to convert sound waves into electrical vibrations.

• 30. The rotational effect of a force on a body about an axis of rotation is described in terms of

  1. Centre of gravity
  2. Centripetal force
  3. Centrifugal force
  4. Moment of force

  Answer :

  Option D

• 31. Which instrument is used to measure sound under water ?

  1. Hygrometer
  2. Hygroscope
  3. Hypsometer
  4. Hydrophone

  Answer :

  Option D

  Explanation:

  Hygrometer - is used to measure level of humidity,
  
  Hygroscope - shows the changes in atmospheric humidity,
  
  Hypsometer - is used to determine the boiling points of liquids.

• 32. Which instrument is used to measure the power of electric circuit ?

  1. Voltmeter
  2. Wattmeter
  3. Wavemeter
  4. Viscometer

  Answer :

  Option B

  Explanation:

  Voltmeter - is used to measure electric potential difference between two points,
  Wavemeter - is used to measure the wavelength of a radiowave,
  Viscometer - is used measure viscosity of liquid.
  

• 33. What is unit of Astronomical distance ?

  1. light year
  2. angstrom
  3. weber
  4. lux

  Answer :

  Option A

  Explanation:

  angstrom is used to measure wave length,
  
  weber is used to measure Magnetic flux,
  
  lux is used to measure Intensity of illumination.

• 34. When a body is immersed partly or wholly in a liquid, there is an apparent loss in weight of the body which is equal to the weight of liquid displaced by the body.

  1. True
  2. False

  Answer :

  Option A

  Explanation:

  TRUE, it is Archimedes Principle.

• 35. Alfred Nobel invented

  1. X ray
  2. Diesel Engine
  3. Dynamite
  4. Dynamo

  Answer :

  Option C

  Explanation:

  Alfred Nobel if Sweden invented Dynamite in 1867,
  
  X ray was invented by Wilhelm Roentgen of Germany in 1895,
  
  Diesel Engine was invented by Rudolf Diesel of Germany 1892,
  
  Dynamo was invented by Michael Faraday of England in 1831.