Wave Motion Questions: Paper - 02 <> More Physics Questions
 1 A transverse wave given by y = 2 sin (0.01x + 30t) moves on a stretched string from one end to another end is 0.5 sec. if x and y are in cm and t is in sec, then the length of the string is (a) 6 m (b) 9 m (c) 12 m (d) 15 m Answer: (d) 2 Two waves are represented by x1 = A sin and x2 = A cos wt, then the pase difference between them is (a) (b) (c) (d) p Answer: (c) 3 The displacement y (in cm) produced by a simple harmonic wave is given by the periodic time and maximum velocity o the particles in the medium will respectively be (CPMT-86) (a) 10-3 sec and 330 m/s (b) 10-4 sec and 20 m/s (c) 10-3 sec and 200 m/s (d) 10-2 sec and 2000 cm/s. Answer: (c) 4 Two sound waves are given by y = a sin (wt - kx) and y’ = b cos (wt - kx). The phase difference between the two waves is (EAMCET-89) (a) (b) (c) p (d) Answer: (a) 5 The equation of a progressive wave is given by, y = 5 sin p m, then the frequency of the wave is (a) 100 Hz (b) 50 Hz (c) 25 Hz (d) 10 Hz Answer: (c) 6 If V is the velocity of the wave and w is the angular velocity, then the propagation constant (K) of the wave is given by (a) (b) (c) K = 2pn (d) Answer: (b) 7 Two sounding bodies producing progressive wave given by y1 = 4 sin 400 pt and y2 = 4 sin 404 pt are situated very near to the ears of a person who will hear (CPMT-88) (a) 2 beats per second with intensity ratio (4/3) between maxima and minima (b) 2 beats per second with intensity ratio (49/1) between maxima and minima (c) 4 beats per second with intensity ratio (7/1) between maxima and minima (d) 4 beats per second with intensity ratio (4/3) between maxima and minima Answer: (b) 8 56 tuning forks are so arranged in series, that each fork gives 4 beats/second with the previous one. If the frequency of the last fork is 3 times that of the first, then the frequency of the first fork will be (a) 55 Hz (b) 110 Hz (c) 75 Hz (d) 220 Hz Answer: (b) 9 The speed of sound in air at N.T.P. is 300 m/s. if air pressure becomes four times, then the speed of sound will be (NCERT-73, CPMT-91) (a) 150 m/s (b) 300 m/s (c) 600 m/s (d) 1200 m/s Answer: (b) 10 Two sound waves having a phase difference of 60° have path difference of (CBSE 96) (a) 2 l (b) (c) (d) Answer: (c) 11 The velocity of sound is measured in hydrogen and oxygen at a certain temperature. The ratio of the velocities is, (CPMT-76) (a) 1:1 (b) 1:2 (c) 1:4 (d) 4:1 Answer: (d) 12 Consider the following statements: Assertion A : The velocity of sound in the air increases due to presence of moisture in it Reason (R) : The presence of moisture in air lowers the density of air. Of these statements (SCRA-94) (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 Answer: (a) 13 If the amplitude of waves at a distance r from a line source is A, then amplitude at a distance 4 r will be: (a) 2A (b) A (c) (d) Answer: (d) 14 The equation of a progressive wave traveling on a string is y = 4 sin cm. the velocity of the wave is (MPPMT-90) (a) 64 cm/s along + x direction. (b) 64 cm/s along - x direction. (c) cm/s along + x direction (d) cm/s along - x direction Answer: (c) 15 What is the phase difference between two successive crest in the wave? (MHT CET 2004) (a) p (b) (c) 2p (d) 4p Answer: (c) 16 If the amplitude of sound is doubled and the frequency reduced to one-fourth, the intensity of sound at the same point will be (CBSE-92) (a) Increasing by a factor of 2 (b) Decreasing by a factor of 2 (c) Decreasing by a factor of 4 (d) Unchanged Answer: (c) 17 Which of the following expressions is that of a simple harmonic progressive wave (CPMT-75) (a) a sin wt (b) a sin (wt) cos (kx) (c) a sin (wt - kx) (d) a cos kx Answer: (c) 18 Frequency of tuning forks are 320 Hz. And 325 Hz. If they are sounded together, the beat period is……. (MHT CET 2003) (a) 5 second (b) 6 second (c) 0 second (d) 0.2 second Answer: (d) 19 A wave equation which gives the displacement along the Y direction is given by y = 10-4 sin(60t + 2x), where x and y are in metres and t is time in seconds. This represents a wave (MNR-83, IIT-82) (a) Traveling with a velocity of 30 m/s in the negative x direction (b) Of wavelength x metre (c) Of frequency hertz. (d) All of the above Answer: (d) 20 Equation of progressive wave is given by y = 4 sin p then which of he following is correct? (CBSE 93) (a) n = 5 cm (b) l = 18 m (c) a = 0.04 m (d) f = 50 Hz Answer: (b) 21 The velocity of sound in any gas depends upon (CBSE-92) (a) Wavelength of sound only (b) Density and elasticity of gas (c) Intensity of sound waves only (d) Amplitude and frequency of sound Answer: (b) 22 The amplitude of two waves are in the ratio 5:2. if all other conditions for the two waves are same, then what is the ratio of their energy densities? (MHT-CET 2004) (a) 5 : 2 (b) 10 : 4 (c) 2.5 : 4 (d) 25 :4 Answer: (d) 23 Ultrasonic waves are those waves (CPMT-79, NMR-83) (a) To which man can hear (b) Man can not hear (c) Are of high velocity (d) Of high amplitude Answer: (b) 24 The velocity of sound in air at 4 atmosphere and that at 1 atmosphere pressure would be (CPMT-79) (a) 1 : 1 (b) 4 : 1 (c) 1 : 4 (d) 3 : 1 Answer: (a) 25 To demonstrate the phenomenon of beats we need (a) Two sources which emit radiation of nearly the same frequency (b) Two sources which emit radiation of exactly the same frequency (c) Two sources which emit radiation of exactly the same frequency and have a definite phase relationship (d) Two sources which emit radiation of exactly the same wavelength Answer: (a)