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Physics

105 questions in Science & Technology.

Asked in 2007, 2006, 2004, 2003, 2002

2007 · Q110Science & TechnologyPhysicsmoderate

Assertion (A): A jet aircraft moving at Mach number equal to 1 travels faster at an altitude of 15 km than while moving at Mach number equal to 1 near sea level. Reason (R): The velocity of sound depends on the temperature of the surrounding medium.

  1. (a)Both A and R are true and R is the correct explanation of A
  2. (b)Both A and R are true but R is NOT the correct explanation of A
  3. (c)A is true but R is false
  4. (d)A is false but R is true
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Official answer(d) A is false but R is true

2006 · Q95Science & TechnologyPhysicsmoderate

There are 8 equidistant points A, B, C, D, E, F, G and H in the clockwise direction on the periphery of a circle. In a time-interval t, a person reaches from A to C with uniform motion while another person reaches the point E from the point B during the same time-interval with uniform motion. Both the persons move in the same direction along the circumference of the circle and start at the same instant. How much time after the start will the two persons meet each other?

  1. (a)4t
  2. (b)7t
  3. (c)9t
  4. (d)Never
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Official answer(b) 7t

2004 · Q72Science & TechnologyPhysicsmoderate

Assertion (A): In our houses, the current in AC electricity line changes direction 60 times per second. Reason (R): The frequency of alternating voltage supplied is 60 hertz.

  1. (a)Both A and R are individually true and R is the correct explanation of A
  2. (b)Both A and R are individually true but R is not the correct explanation of A
  3. (c)A is true but R is false
  4. (d)A is false but R is true
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Official answer(a) Both A and R are individually true and R is the correct explanation of A

2004 · Q125Science & TechnologyPhysicseasy

A spherical body moves with a uniform angular velocity ω around a circular path of radius r. Which one of the following statements is correct?

  1. (a)The body has no acceleration
  2. (b)The body has a radial acceleration ω²r directed towards the centre of the path
  3. (c)The body has a radial acceleration 2/5 ω²r directed away from the centre of the path
  4. (d)The body has an acceleration ω²r tangential to its path
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Official answer(b) The body has a radial acceleration ω²r directed towards the centre of the path

2003 · Q22Science & TechnologyPhysicsmoderate

Consider the following statements: 1. Steam at 100 °C and boiling water at 100 °C contain the same amount of heat. 2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water. 3. In an air-conditioner, heat is extracted from the room air at the evaporator coils and is rejected out at the condenser coils. Which of these statements is/are correct?

  1. (a)1 and 2
  2. (b)2 and 3
  3. (c)Only 2
  4. (d)Only 3
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Official answer(d) Only 3

2003 · Q63Science & TechnologyPhysicseasy

Which one of the following statements is correct?

  1. (a)The velocity of sound in air increases with the increase of temperature
  2. (b)The velocity of sound in air is independent of pressure
  3. (c)The velocity of sound in air decreases as the humidity increases
  4. (d)The velocity of sound in air is not affected by the change in amplitude and frequency
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Official answer(c) The velocity of sound in air decreases as the humidity increases

2002 · Q69Science & TechnologyPhysicsmoderate

Consider the following statements: 1. Light of longer wavelength is scattered much more than light of shorter wavelength. 2. The speed of visible light in water is 0.95 times its speed in vacuum. 3. Radio waves are produced by rapidly oscillating electrical currents. 4. To detect over-speeding vehicles, police use the Doppler effect of reflected short radio waves. Which of these statements are correct?

  1. (a)1 and 2
  2. (b)1 and 3
  3. (c)2 and 4
  4. (d)3 and 4
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Official answer(d) 3 and 4