Mock Test

Sound

by Anish
Updated On:

Sound

Total Questions: 56

31. The velocity of sound is maximum in : [U.P. Lower Sub (pre) 2008 Uttarakhand P.C.S. (PRE) 2010]

Correct Answer: (c) metal
Solution:The speed of sound varies from medium to medium sound travels most slowly in gases it travels faster in liquids and fastest in solids for example sound travels at 331 m/s in air it travels at 1531 m/s in iron.

32. If Va, Vw, and Vs respectively are the speed of sound in air water and steel then : [U.P.U.D.A./L.D.A.(spl)(mains) 2010]

Correct Answer: (a) Va< Vw< Vs
Solution:As we know that the speed of sound is different for different types of medium in general sound travels faster in liquid than gases and faster in solids than in liquid.

33. In which medium the speed of sound is maximum at a temperature of around 20ºC ? [Chhattisgarh P.C.S.(PRE) 2004]

Correct Answer: (d) iron
Solution:The speed of sound depends on the elasticity and density of the medium through which it is travelling, greater the elasticity and the density sound travel faster in that medium, at a temperature 20ºC the speed of sound is maximum in iron.

34. Sound waves : [U.P.P.C.S.(pre) 2002]

Correct Answer: (d) can travel both in solids and gases medium.
Solution:
  • Sound waves are mechanical waves: This means they require a medium (like a solid, liquid, or gas) to travel. They propagate by causing vibrations in the particles of the medium.
  • Solids: Sound travels very well through solids because the particles are closely packed, allowing vibrations to be transmitted efficiently.
  • Liquids: Sound also travels through liquids, though generally slower than in solids.
  • Gases: Sound travels through gases, like air, but at a slower speed compared to solids and liquids due to the greater spacing between gas particles.
  • Vacuum: Sound cannot travel through a vacuum because there are no particles to vibrate.

35. Sound waves travel fastest in : [M.P.P.C.S.(PRE) 2017]

Correct Answer: (a) solids
Solution:
  • Sound waves are mechanical waves: This means they require a medium (like a solid, liquid, or gas) to travel. They propagate by causing vibrations in the particles of the medium.
  • Solids: Sound travels very well through solids because the particles are closely packed, allowing vibrations to be transmitted efficiently.
  • Liquids: Sound also travels through liquids, though generally slower than in solids.
  • Gases: Sound travels through gases, like air, but at a slower speed compared to solids and liquids due to the greater spacing between gas particles.
  • Vacuum: Sound cannot travel through a vacuum because there are no particles to vibrate. hence sound travel faster in solid.

36. In which of the following option sound may not be across /travel ? [U.P.P.C.S.(pre) 1990]

Correct Answer: (b) vacuum
Solution:Sound is a mechanical wave and needs a material medium like air ,water and steel etc for its propagation. it cannot travel through vacuum.

37. Sound waves do not travels in : [U.P.P.C.S.(pre) 2014]

Correct Answer: (d) vacuum
Solution:Sound is a mechanical wave and needs a material medium like air, water and steel etc for its propagation. so it cannot travel through vacuum.

38. The walls of the hall built for music concerts should : [U.P.P.C.S.(MAINS) 2007]

Correct Answer: (a) absorb sound.
Solution:The walls of the hall built for music concerts should absorb sounds(to prevent echoes and reverberation). Most of the solids walls reflects the sound, if the walls of concert hall reflect the sound then the audience hear the echo sound. so to avoid this there is a need to built soft surface walls.

39. Which of the following is a cause of echo ? [Jharkhand P.C.S. (PRE) 2023]

Correct Answer: (c) reflection of sound.
Solution:An echo is a effect of sound caused by the reflection of sound wave from a surface back to the listener, it is reflection of sound arriving at the listener sometimes after the direction sound .

40. To hear a clear echo the minimum distance between the reflecting surface and the observer should be : [U.P.P.C.S.(MAINS) 2007]

Correct Answer: (d) 16.5 metre
Solution:The repetition of sound produced due to the reflection from a large surface like wall, hill or mountain is called echo. Consider an observer is producing a sound and it gets reflected by an obstacle.

The sound travel towards the observer and the observer hear the sound again. Let 'd' be the distance between the observer and the obstacle, 'v' is the sound velocity and 't' is the time taken by the sound to and fro motion, then the velocity of the sound is given by

v = 2 ×d / t
Substituting t= 1/10 sec, it is minimum time required to distinguish between two sounds for listening echo.

v=velocity of sound =330 m/sec at 20°C
then d = (v ×t)/2 = 1/2 × [330(1/10)]
=16.5 m (about 17 m).

Anish

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