Physics Questions Answers

• 36. What is unit of Astronomical distance ?

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

  Answer And Explanation

  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.

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• 37. Scalar Quantities are

  1. physical quantities which have magnitude only and no direction
  2. physical quantities which have no magnitude only and only direction
  3. physical quantities which have magnitude only and direction
  4. physical quantities which have no magnitude and no direction

  Answer And Explanation

  Answer: Option A

  Explanation:

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• 38. What is displacement ?

  1. Longest distance covered by a body in a random direction.
  2. Shortest distance covered by a body in a random direction.
  3. Shortest distance covered by a body in a definite direction.
  4. Longest distance covered by a body in a definite direction.

  Answer And Explanation

  Answer: Option C

  Explanation:

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• 39. Which law is also called law of inertia ?

  1. Newton first law
  2. Newton second law
  3. Newton third law
  4. All of above

  Answer And Explanation

  Answer: Option A

  Explanation:

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• 40. What is newton third law of motion ?

  1. Every body maintains its initial state rest or motion unless no external force is applied.
  2. The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
  3. To every action there is equal and opposite reaction.
  4. None of above.

  Answer And Explanation

  Answer: Option C

  Explanation:

  Newton First Law of Motion : Every body maintains its initial state rest or motion unless no external force is applied.
  
  Newton Second Law of Motion : The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.

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• 41. If no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. Which law states this ?

  1. Newton first law
  2. Newton second law
  3. Newton third law
  4. Principle of conservation of linear momentum

  Answer And Explanation

  Answer: Option D

  Explanation:

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• 42. 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 And Explanation

  Answer: Option D

  Explanation:

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