MCQs on Sound Asked in PYQs Set – 2
Q21. The optimum sound level for human beings is [RAS/RTS (Pre) 2012]
[A] 90 dB
[B] 60 dB
[C] 120 dB
[D] 100 dB
Q22. A worker was working on the rail track. A boy at a distance holds his ear near the rail track. This boy was able to hear sound of the blow of workman twice. It is because of [RAS/RTS (Pre) 1994, 95]
[A] The speed of sound is greater in steel than in air
[B] The speed of sound is greater in air than in steel
[C] Part of the sound wave is reflected between the rail tracks
[D] His ears are at different distance from the source
Q23. As per the WHO, the safe noise level for a city is [UPPCS (Mains) 2010]
[A]Â 45 dB
[B] 50 dB
[C] 55 dB
[D] 60 dB
Q24. Which one of the following is the effect of the flight of a supersonic jet? [MPPCS (Pre) 1993]
[A] Air pollution
[B] Eye disease
[C] Depletion in the ozone layer
[D] None of the above
Q25. What is the purpose of ‘evolved Laser Interferometer Space
Antenna (eLISA)’ project? [IAS (Pre) 2017]
[A] To detect neutrinos
[B] To detect gravitational waves
[C] To detect the effectiveness of missile defence system
[D] To study the effect of solar flares on our communication systems
Q26. The technique used to transmit audio signals in television broadcasts is [Tamil Nadu PSC (Pre) 2019 UP UDA/LDA (Spl)(Pre) 2010]
[A] Amplitude modulation
[B] Pulse code modulation
[C] Frequency modulation
[D] Time dimension multiplication
Q27. Decibel is used to measure [MPPCS (Pre) 2005]
[A] Haemoglobin in the blood
[B] Sugar in urine
[C] Sound in atmosphere
[D] Particles in air
Q28. Assertion [A]: Reverberation mainly occurs in large churches and other large buildings.
Reason (R): The walls, roof and ground may cause multiple sound reflections.
[UP Lower Sub. (Spl) (Pre) 2003, 02]
Code
[A] Both [A] and (R) are true and (R) is the correct explanation of [A]
[B] Both [A] and (R) are true, but (R) is not the correct explanation of [A]
[C] [A] is true, but (R) is false
[D] [A] is false, but (R) is true
Q29. Which of the following has the longest wavelength? [RAS/RTS (Pre) 1996]
[A] Infrared
[B] X-rays
[C] Visible light
[D] Radio waves
Q30. The Doppler’s effect is applicable for [Jharkhand PCS (Pre) 2013
UP UDA/LDA (Pre) 2010 UPPCS (Pre) 2010, 2002]
[A] Light waves
[B] Sound waves
[C] Space waves
[D] Both [A] and [B]
Q31. Ultrasonics are sound waves of frequency [UPPCS (Pre) 2012]
[A] Greater than 20,000 Hz
[B] Less than 10,000 Hz
[C] Equal to 1000 Hz
[D] None of the above
Q32. When T.V. is switched on [UPPCS (Pre) 2007]
[A] Audio and video both start simultaneously
[B] Audio is heard immediately but the video starts later because the video needs some warm-up time
[C] Video starts immediately but audio is heard later because sound travels at a lesser speed than light
[D] It depends on the T.V. brand
Q33. A radio station broadcast at 30-metre band. The frequency of the carrier wave transmitted by this station is [Goa PSC (Pre) 2016 RAS/RTS (Pre) 1993]
[A] 10 kHz
[B] 100 kHz
[C] 10 MHz
[D] 100 MHz
Q34. An astronaut cannot hear his companion at the surface of the Moon because [UPPCS (Mains) 2013]
[A] Produced frequencies are above the audio frequency
[B] Temperature is too low during the night and too high during the day
[C] There is no medium for sound propagation
[D] There are many craters on the surface of the Moon
Q35. Put in ascending order the speed of sound in the mediums.
[Orissa PSC (Pre) 2014 UPPCS (Spl)(Mains) 2008]
1. Water
2. Steel
3. Nitrogen
[A] 3, 2, 1
[B] 3, 1, 2
[C] 1, 3, 2
[D] 2, 1, 3
Q36. Consider the following statements.
1. A flute of a smaller length produces waves of lower frequency.
2. Sound travels in rocks in the form of longitudinal elastic waves only.
Which of the statements given above is/are correct? [Mizoram PSC (Pre) 2019 IAS (Pre) 2007]
[A] Only 1
[B] Only 2
[C] Both 1 and 2
[D] Neither 1 nor 2
Q37. Consider the following statements about ultrasonic waves.
- They can destroy insects.
- They can clean clothes by removing dust.
- They can be used to treat diseases.
- They can control automatic doors.
Of the above statements. [UPPCS (Mains) 2004]
[A] 1 and 2 are correct
[B] 3 and 4 are correct
[C] 1, 2 and 3 are correct
[D] All are correct
Q38. Which one of the following does a TV remote control unit use to operate a TV set? [UPPCS (Mains) 2013 IAS (Pre) 2000]
[A] Light waves
[B] Sound waves
[C] Microwaves
[D] Radio waves
Q39. Consider the following statements.
- The heart vibrates at infrasonics.
- The speed of sound is more in gas than in liquid and solid.
- Mach number is used to describe the speed of sound.
- Ultrasonic sound has a frequency of more than 20,000 Hz.
Of these statements. [UPPCS (Mains) 2002]
[A] 1, 2 and 3 are correct
[B] 2, 3 and 4 are correct
[C] 1, 3 and 4 are correct
[D] 1, 2 and 4 are correct
Q40. When the same note is played on a sitar and a flute, the sound produced can be distinguished from each other because of the difference in [IAS (Pre) 1995]
[A] pitch, loudness and quality
[B] pitch and loudness
[C] quality only
[D] loudness only
Q41. In television broadcasts, the picture signals are transmitted by [RAS/RTS (Pre) 2012]
[A] Amplitude modulation
[B] Frequency modulation
[C] Phase modulation
[D] Angle modulation
Q42. Which type of electromagnetic radiation is used in the remote control of a television? [UPPCS (Pre) 2013]
[A] Infra-red
[B] Ultraviolet
[C] Visible
[D] None of these
Q43. 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 the sea level.
Reason (R): The velocity of sound depends on the temperature of the
surrounding medium. [IAS (Pre) 2007]
Code
[A] Both [A] and (R) are true and (R) is the correct explanation of [A]
[B] Both [A] and (R) are true, but (R) is not the correct explanation of [A]
[C] [A] is true, but (R) is false
[C] [A] is false, but (R) is true
Q44.
Assertion [A]: Radio waves bend in a magnetic field.
Reason (R): Radio waves are electromagnetic in Nature. [IAS (Pre) 2008]
Code
[A] Both [A] and (R) are true and (R) is the correct explanation of [A]
[B] Both [A] and (R) are true, but (R) is not the correct explanation of [A]
[C] [A] is true, but (R) is false
[D] [A] is false, but (R) is true
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