Physics Questions Answers

  • 64. What is unit of Work and Energy ?

    1. Joule
    2. kilogram
    3. amphere
    4. meter
    Answer :

    Option A

  • 65. Which of the following is an electromagnetic wave ?

    1. Cathode rays
    2. Sound wave
    3. Ultrasonic wave
    4. Infra red rays
    Answer :

    Option D

  • 66. Harry Brearley has invented

    1. Electric iron
    2. Electromagent
    3. Stainless Steel
    4. Gramophone
    Answer :

    Option C

    Explanation:

    Harry Brearley of England has invented Stainless Steel in 1913,

    Electric iron has been invented by H.W. Seeley of USA in 1882,

    Electromagent has been invented by W.Sturgeon of England in 1824,

    Gramophone has been invented by T.A. Edison of USA in 1878.

  • 67. Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings."

    1. Doppler's Effect
    2. Newton's law of cooling
    3. Kirchhoff's Law
    4. Stefan's Law
    Answer :

    Option B

    Explanation:

    Doppler's Effect - The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.

    Kirchhoff's Law - Kirchhoff's Law signifies that good absorbers are good emitters.

    Stefan's Law - The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.

  • 68. Electric Motor converts

    1. Electrical energy into mechanical energy
    2. Mechanical energy into Electrical energy
    3. Electrical energy into light energy
    4. None of above
    Answer :

    Option A

  • 69. Name of the instrument to measure atomspheric pressure ?

    1. Barometer
    2. Barograph
    3. Bolometer
    4. Callipers
    Answer :

    Option A

    Explanation:

    Barograph - Recordings of atmospheric pressure,
    Bolometer - Used to measure heat radiation,
    Callipers - Used to measure inner and outer diameters of bodies.

  • 70. Which instrument is used to measure changes in volume of substances ?

    1. Dyanamo
    2. Dilatometer
    3. Cyclotron
    4. Electroscope
    Answer :

    Option B

    Explanation:

    Dyanamo - is used to convert mechanical energy into electrical energy,

    Cyclotron - is a charged particle accelerator which can accelerate charged particles to high energies,

    Electroscope - is used to detect the presence of an electric charge.

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