Physics - 02

01. Supersonic plane fly with the speed

  • 1less than the speed of sound
  • 2of sound
  • 3greater than the speed of sound
  • 4of light
Answer:- 1
Explanation:-

No explanation is given for this question Let's Discuss on Board

02. Light from the star, Alpha Centauri, which is nearest to the earth after the sun, reaches the earth in

  • 14.2 seconds
  • 242 seconds
  • 34.2 years
  • 442 years
Answer:- 1
Explanation:-

No explanation is given for this question Let's Discuss on Board

03. Mercury is commonly used as a thermometric fluid rather than water because

  • 1specific heat of mercury is less than water
  • 2specific heat of mercury is more than water
  • 3mercury has greater visibility than water
  • 4density of mercury is more than the water
Answer:- 1
Explanation:-

Solution:
Mercury has greater visibility than water.

04. Out of the following pairs, which one does not have identical dimension?

  • 1Moment of inertia and moment of a force
  • 2Work and Torque
  • 3Angular momentum and Planck's constant
  • 4Impulse and Momentum
Answer:- 1
Explanation:-

Solution:
Moment of inertia and moment of a force.

05. Light Emitting Diodes (LED) is used in fancy electronic devices such as toys emit

  • 1X-rays
  • 2ultraviolet light
  • 3visible light
  • 4radio waves
Answer:- 1
Explanation:-

Solution:
Visible light.

06. Radio telescopes are better than optical telescopes because

  • 1they can detect faint galaxies which no optical telescope can
  • 2they can work even in cloudy conditions
  • 3they can work during the day and night
  • 4All of the above
Answer:- 1
Explanation:-

Solution:
All of the above.

07. Intensity of sound at a point is ____ its distance from the source.

  • 1directly proportional to
  • 2inversely proportional to
  • 3directly proportional to square of
  • 4inversely proportional to square of
Answer:- 1
Explanation:-

Solution:
Intensity of sound at a point is inversely proportional to square of its distance from the source.

08. Sound produced at a point is heard by a person after 5 second, while the same sound is heard by another person after 6 seconds. If the speed of sound is 300 m/s, what could be the maximum and minimum distances between the two persons?

  • 11.8 km, 0.15 km
  • 22.2 km, 0.20 km
  • 32.8 km, 0.25 km
  • 43.3 km, 0.30 km
Answer:- 1
Explanation:-

Solution:
3.3 km, 0.30 km.

09. On a cold day when a room temperature is 15oC, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15oC, because

  • 1metals have higher thermal capacity than plastics
  • 2plastics have a lower density than metals
  • 3metals are good conductor of heat
  • 4plastics have a higher thermal conductivity than metals
Answer:- 1
Explanation:-

Solution:
Metals are good conductor of heat.

10. Railway tracks are banked on curves

  • 1necessary centrifugal force may be obtained from the horizontal component weight of the train
  • 2to avoid frictional force between the tracks and wheels
  • 3necessary centripetal force may be obtained from the horizontal component of the weight of the train
  • 4the train may not fly off in the opposite direction
Answer:- 1
Explanation:-

Solution:
Necessary centripetal force may be obtained from the horizontal component of the weight of the train.

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