CBSE Class 11 science: Behaviour of Progressive Waves Videos | Speed of Progressive Waves - Exam Decoded

• If the frequency of a tuning fork is 400 Hz and the velocity of sound in air 320 m/s, find how far does the sound travel when the fork executes 30 vibrations?
• On the basis of Laplace's correction, calculate the velocity of sound in air at N.T.P.
• Show that the velocity of sound increases by 61 cm/s for every 1^oC.
• A steel wire has a length of 12.0 m and a mass of 2.10 kg.  What should be the tension in the wire so that the speed of a transverse wave on the wire equals the speed of sound in dry air at 20^oC?  Take the speed of sound at 20^oC = 343 m/s.
• A bat emits ultrasonic sound of frequency 100 kHz in air.  If this sound meets a water surface, what is the wavelength of (i)  the reflected sound, (ii)  the transmitted sound?  Speed of sound in air = 340 ms^-1 and in water = 1486 ms^-1.
• A transverse harmonic wave on a string is described by  where x , y are in cm and t in seconds.  The positive direction of x is from left to right. (a)  Is this a travelling or a stationary wave?  If this is travelling, then what is the speed and direction of its propagation? (b)  What is its amplitude and frequency? (c)  What is the initial phase at the origin? (d)  What is the least distance between two successive crests in the wave?  
• The displacement of particle in wave equation is represented as y = 1.2 sin (120 πt - 0.20x) If this is made to incident on the rigid wall and its amplitude falls to 40% reflection from wall, then what is the equation of reflected wave?
• The transverse displacement of a string (clamped at its two ends) is given by where x, y are in meter and t is in second.  The length of the string is 1.5 m and its mass is 3.0 x 10^-2kg. Answer the following : (a)  What are the wavelength, frequency and speed of propagation of each wave? (b)  Determine the tension in the string.
• An engine approaches a high vertical wall with constant speed of 90 m/sec.  When it is at a distance of 1050 m from the wall, it blows a whistle, whose echo is heard after 5 second.  Calculate the speed of sound in air.
• State principle of superposition.

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