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Wave Motion

1. In a transverse wave of amplitude A, the maximum particle velocity is four times wave velocity, then the wave length of the wave is-

Ans: 
 

2. A wave has a frequency of 120 Hz. Two points at a distance of 9m apart have a phase difference of 1080o. The velocity of the wave is-
Ans: 360 m/s

 

3.The linear density of a vibrating string is 1.3 × 10-4 kg/m. The transverse wave propagating along the string is described by y = 0.021 sin (x + 30 t) where x is in meter and t is in second. The tension in the string is-
Ans: 0.12 N 

 

4. The fundamental frequency of a sonometer wire is 200 Hz. When a body whose relative density 4 is suspended at the free end of wire. The fundamental frequency of the same wire when the suspended body is made to immerse in water is-
Ans: 

 

5. A steel wire of length 1.5m has density 7.7 × 103 kg/m3 and Young's modules 2.2 × 1011 N/m2. It is subjected to a tension which produces an elastic strain of 1%. Its fundamental frequency of vbibration must be-
Ans: 178 Hz

6. A closed organ pipe is vibrating in first overtone and is in resonance with another open organ pipe vibrating in third harmonic. The ratio of lengths of the pipes respectively is-
Ans: 1 : 2

 

7. To increase the frequency by 20%, the tension in the string vibrating on a sonometer has to be increased by-
Ans: 44%

 

8. Two sources A and B are sending notes of frequency 680 Hz. A listener moves from A to B with a constant velocity 'u'. If the speed of sound in air is 340 ms-1 what must be the value of 'u' so that he hears 10 beats per second?
Ans: 2.5 ms-1

 

9. A source emits a sound of frequency of 400 Hz, but the listener hears it to be 390 Hz then-
a) The listener is moving towards the source.
b) The source is moving towards the listener.
c) The listener is moving away from the source.
d) The source is moving away from the listener.
Ans: both (c) and (d)

10. A source of sound of frequency 1000 Hz is on a table rotating at 5 r.p.s. at a distance 0.7 m from the centre of the table. If the velocity of sound in air is 352 ms-1, the maximum frequency heard by a stationary listener out side the table?
Ans: 1067 Hz

 

11. A fork gives 5 beats with a 40 cm length of sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is-
Ans: 395

 

12. A tonometer consists of 16 forks, each fork produces 4 beats/ second with the next. If the lowest frequency is 60 Hz, what is the highest frequency?
Ans: 120 Hz

 

13. A person standing between two parallel hills fires a gun. He hears the first echo after 1.5 second and second echo after 2.5 second. If the speed of sound is 332 ms-1, calculate the distance between the hills. When will he hear the third echo-
Ans: 664 m, 4S

14. A theatre of volume 100 × 40 × 10 m3 can accommodate 1000 visitors. The reverberation time of the theatre when empty is 8.5 sec. If the theatre is now filled with 500 visitors, occupying the front-half seats, the reverberation time changes to 6.2 seconds. The average absorption coefficient of each visitor is nearly-
Ans: 0.6

 

15. Which of the following does not effect the reverberation time-
1) Size of the auditorium                2) Frequency of sound
3) Nature of the walls                     4) Area of the walls, ceiling and floor
Ans: Frequency of sound

Posted Date : 15-10-2020

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గమనిక : ప్రతిభ.ఈనాడు.నెట్‌లో కనిపించే వ్యాపార ప్రకటనలు వివిధ దేశాల్లోని వ్యాపారులు, సంస్థల నుంచి వస్తాయి. మరి కొన్ని ప్రకటనలు పాఠకుల అభిరుచి మేరకు కృత్రిమ మేధస్సు సాంకేతికత సాయంతో ప్రదర్శితమవుతుంటాయి. ఆ ప్రకటనల్లోని ఉత్పత్తులను లేదా సేవలను పాఠకులు స్వయంగా విచారించుకొని, జాగ్రత్తగా పరిశీలించి కొనుక్కోవాలి లేదా వినియోగించుకోవాలి. వాటి నాణ్యత లేదా లోపాలతో ఈనాడు యాజమాన్యానికి ఎలాంటి సంబంధం లేదు. ఈ విషయంలో ఉత్తర ప్రత్యుత్తరాలకు, ఈ-మెయిల్స్ కి, ఇంకా ఇతర రూపాల్లో సమాచార మార్పిడికి తావు లేదు. ఫిర్యాదులు స్వీకరించడం కుదరదు. పాఠకులు గమనించి, సహకరించాలని మనవి.

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