Answered 0 of 25 on this page · Correct 0 · Wrong 0
Q26. Supersonic aircraft fly in-
- Aat the speed of sound
- Bat a speed less than the speed of sound
- Cfaster than the speed of sound
- Dat the speed of light
Show answer & explanation
Answer: C) faster than the speed of sound
Q27. The ratio of the velocity of an object to the velocity of sound in the same medium and under the same conditions is called-
- APlace number
- BDurability Number
- Coctane number
- DMach number
Show answer & explanation
Answer: D) Mach number
Q28. Mach numbers are used in relation to velocity.
- Aof sound
- Bof the vessel
- Cof the aircraft
- Dof the spacecraft
Show answer & explanation
Answer: C) of the aircraft
Q29. Noise or noise pollution is measured by-
- Ain phone
- Bin Desi
- Cin decibels
- Din decimals
Show answer & explanation
Answer: C) in decibels
Q30. The intensity of sound of ordinary conversation is-
- A20-30dB
- B30-40 dB
- C50-60dB
- D90-100 dB
Show answer & explanation
Answer: B) 30-40 dB
Q31. What is the characteristic of sound that distinguishes a female voice from a male voice called?
- Apitch
- Bphase
- Cquality
- Dintensity
Show answer & explanation
Answer: A) pitch
Q32. Due to which characteristic of sound a sound becomes thick or thin?
- Aintensity
- Bpitch
- Cquality
- DNone of these
Show answer & explanation
Answer: B) pitch
Q33. Women's voice is sharper than men's because women's voice has-
- AThe amplitude is reduced
- BThe amplitude is higher
- CThe pitch is low,
- Dthe pitch is higher
Show answer & explanation
Answer: D) the pitch is higher
Q34. Why is the voice of a small child more pleasant than the voice of a young man?
- AThe pitch of a child's voice is lower than that of a man's voice.
- BThe pitch of a child's voice is higher than that of a man's voice
- CThe child has more strength
- Dnone of the above
Show answer & explanation
Answer: B) The pitch of a child's voice is higher than that of a man's voice
Q35. The voice of women is thinner than that of men because the voice of women-
- Ahas a higher frequency
- Bhas a greater wavelength.
- Chas a greater amplitude
- Dhas a greater velocity
Show answer & explanation
Answer: A) has a higher frequency
Q36. If the same note is played on sitar and flute, then the difference in the sound produced by them can be made due to the difference in the following:
- Apitch, loudness and quality
- Bpitch and loudness only
- Csound loudness only
- DSound quality only
Show answer & explanation
Answer: D) Sound quality only
Q37. Which one of the following is not produced by sound waves in air?
- Apolarization
- BDiffraction
- Creflection
- DRefraction
Show answer & explanation
Answer: A) polarization
Q38. The maximum limit of sound intensity in decibels above which a person cannot hear is-
- A50dB
- B70 dB
- C85 dB.
- D95 dB
Show answer & explanation
Answer: D) 95 dB
Q39. Which of the following causes the most noise pollution?
- Amotor vehicle
- BRailway Engine
- CPop music
- Dflying an airplane
Show answer & explanation
Answer: D) flying an airplane
Q40. The whistle of an approaching train increases in volume, while that of a departing train decreases. This phenomenon is an example of:
- ARaman effect
- BJoule Thomson effect
- CCrompton effect
- Dof the Doppler effect
Show answer & explanation
Answer: D) of the Doppler effect
Q41. An astronaut cannot hear his classmate on the surface of the moon because-
- AThe frequency produced is higher than the sound frequency
- BThe temperature is very low at night and very high during the day.
- Cis not a medium for propagating sound
- DThere are many craters on the surface of the Moon.
Show answer & explanation
Answer: C) is not a medium for propagating sound
Q42. Which process does not occur in both light and sound?
- ADiffraction
- Breflection
- Cpolarization
- DRefraction
Show answer & explanation
Answer: C) polarization
Q43. While shouting, a person always keeps his palm near his mouth because-
- AIn that case the sound energy will be pointing in only one direction.
- BSound fullness of sound increases
- CThe fluctuations in the sound tone increase.
- DThis action has no effect on the sound.
Show answer & explanation
Answer: A) In that case the sound energy will be pointing in only one direction.
Q44. Decibel is used to measure which of the following?
- Aspeed of light
- Bintensity of sound
- Cfrequency of radio waves
- Dheat intensity
Show answer & explanation
Answer: C) frequency of radio waves
Q45. The reason for resonance is-
- Areflection of sound
- BRefraction of sound
- CAbsorption of sound
- Dspeed of sound
Show answer & explanation
Answer: A) reflection of sound
Q46. To hear a clear echo, the minimum distance between the reflecting surface and the sound source should be-
- A10 meters
- B17 meters
- C24 meters
- D30 meters
Show answer & explanation
Answer: B) 17 meters
Q47. The working system of radar is based on the following principle-
- ARefraction of radio waves
- BReflection of radio waves
- CDoppler effect
- DRaman effect
Show answer & explanation
Answer: B) Reflection of radio waves
Q48. What should be the time interval between the original sound and the echo to hear an echo?
- Aequal to 1/10 second
- Bless than 1/10-second
- Cmore than 1/10-second
- DNone of these.
Show answer & explanation
Answer: C) more than 1/10-second
Q49. The walls, ceiling and floor of a good auditorium should be made of fibrous material, carpet, glass etc.
- ABeautify the auditorium
- BReducing the cost of construction
- CFire safety in the auditorium
- DAbsorbing sound to prevent echoes
Show answer & explanation
Answer: D) Absorbing sound to prevent echoes
Q50. How long does the effect of sound last in the human ear?
- A1/5 second
- B1/10 second
- C1/20 second
- D1/2 second
Show answer & explanation
Answer: B) 1/10 second