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1 MCQs with One Correct Answer, , In a resonance tube experiment when the tube is filled with, water up toa height of 17.0 cm from bottom, it resonates, with a given tuning fork. When the water level is raised, the next resonance with the same tuning fork occurs at a, height of 24.5 cm. If the velocity of sound in air is 330 m/, s, the tuning fork frequency is: | Main Sep. 05, 2020 (1), (a) 2200Hz (b) SS0Hz (cc) 100H2(d) 3300Hz, A uniform thin rope of length 12 mand mass 6 kg hangs, vertically from a rigid support and a block of mass 2 kg is, attached to its free end. A transverse short wave-train of, wavelength 6 cm is produced at the lower end of the rope., What is the wavelength of the wavetrain (in cm) when it, reaches the top of the rope? —_ | Main Sep. 03, 2020(1)|, (a) 3 (b) 6 ¢) 2 @9, Two identical strings ¥ and Z made of same material have, tension 7, and T, in them. If their fundamental frequencies, are 450 Hz and 300 Hz, respectively, then the ratio 7/7, is:, [Main Sep. 02, 2020 (1)|, (a) 225 (bs) 044 =) :125. 15, A transverse wave travels on a taut steel wire with a, velocity of 7 when tension in it is 2.06 x 10'N. When the, tension is changed to T, the velocity changed to v/2. The, , value of T is close to: [Main 8 Jan. 2020 (11)}, (a) 2.50xl0N (b) S.1SxION, (c) 30.5x10°N (d) 10.2x1N, , Speed of a transverse wave on a straight wire (mass 6.0 g,, 60 cm and area of cross-section 1.0 mm*) is 90 ms”., Ifthe Young's modulus of wire is 16> 10" Nov“ the extension, of wire over its natural length is: {Main 7 Jan. 2020(1)|, (a) 003mm (b) 002mm (c) 004mm = (d)0.01 mm, A heavy ball of mass M is suspended from the ceiling of, acarbya light string of mass m (m<<M). When the car is, at rest, the speced of transverse waves in the string is 60, ms“. when the car has acceleration a, the wave-speed, increases to. 60.5 ms“. The value ofa, in terms of gravitational, acceleration g, is closest to: [Main 9 Jan. 2019 (1)], & & ie &, @ 3 (b) 5 © 49 (d) 20, ‘Atuning fork of frequency 480 Hz is used in an experiment, for measuring speed of sound (v) in air by resonance tube, method. Resonance is observed to occur at two, successive lengths of the air column, f, = 30 cm and /,= 70, cm. Then, v is equal to: {Main 12 April 2019 (11)}, (a) 332ms* (b) 384ms' (c) 338ms'(d) 379 ms", Awirc of length 2L, is made by joining two wires A and B, ofsame length but different radii rand 2r and made of the, same material. It is vibrating at a frequency such that the, joint of the two wires forms a node. If the number of, ‘antinodes in wire A is p and that in B is q then the ratio, p:qis: |Main 8 April 2019 (1)], , , A B ‘, + L—> +L, (a) 3:5 (b) 4:9 () 1:2. @ 1:4

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Ee, , 12,, , 13., , 14., , 16., , A closed organ pipe has a fundamental fr uency of 1.5, tinal Ee number of overtones that ake distinctly, a person with this organ pipe will be: (Assume, that the highest frequency a person can hear is 20,000 Hz), [Main 10 Jan. 2019 (1)|, (a) 6 (b) 4 (c) 7 (d) 5, A granite rod of 60 cm length is clamped at its middle point, and is set into longitudinal vibrations, The density of granite, is2.7 « 10° kg/m? and its Young's modulus is 9.27* 10" Pa, What will be the fundamental frequency of the longitudinal, ? |Main 2018}, (a) Skitz (b) 2SkHz (c) 10kHz (d) 75ktHz, Two wires W, and W, have the same radius r and, Tespective densities P, and p, such that P, = 4p. They, are joined together at the point O, as shown in the figure., The combination is used as a sonometer wire and kept, under tension T. The point O is midway between the two, bridges. When a stationary waves is set up in the, composite wire, the joint is found to be a node. The ratio, of the number of antinodes formed in W, to W, is :, , " |Main Ontine Apri 8, 2017], 1 P2, , Ww, Ww,, (a) 1:1 (b) 1:2 {c) 1:3 (d) 4:1, , A uniform string of length 20 m is suspended from a rigid, support. A short wave pulse is introduced at its lowest, end. It starts moving up the string. The time taken toreach, the supports is : [Main 2016], (take g= 10 ms), , (@) 22s (b) ¥2s (©) 2mV2s d)2s, , A pipe open at both ends has a fundamental frequency f, in air. The pipe is dipped vertically in water so that halfof, it is in water. The fundamental frequency of the air column, , is now : [Main 2016], 2f b) f . id =, (a) (b) (c) 3 (d) 7, , A pipe of length 85 cm is closed from one end. Find the, number of possible natural oscillations of air column in, the pipe whose frequencies lie below 1250 Hz. The velocity, of sound in air is 340 m/s. [Main 2014], (a) 12 (b) 8 (c) 6 (d) 4, , A sonometer wire oflength 1.5 m is made of steel. The tension, in it produces an elastic strain of 1%. What is the fundamental, frequency of steel if density and clasticity of steel are, 7.7 « 103 kg/m} and 2.2 * 10"! Nim? respectively?, , (a) 188SHz (b) 1782Hz |Main 2013}, (ce) 200,SHz (d) 770Hz, , A sonometer wire of length 1 14cm is fixed at both the ends., Where should the two bridges be placed so as to divide the, wire into three segments whose fundamental frequencies, arein the ratio! :3:4? = |Main Online April 23, 2013), {a) At36cm and $4 cm from one end, , {b) At24cm and 72 cm from one end, , ({c) At48cm and 96 cm from one end, , (d) At7?2cm and 96 cm from one end

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17., , 18., , 19,, , 21., , 22., , A student is performing the experiment of resonance, column. The diameter of the column tube is 4 cm. The, frequency of the tuning fork is 512 Hz. The air temperature, is 38°C in which the speed of sound is 336 m/s. The zero of, the meter scale coincides with the top end of the resonance, column tube. When the first resonance occurs, the reading, of the water level in the column is [2012], (a) 140cm (b) 152an (c) 164cm(d) 17.6cn, , A hollow pipe of length 0.8 m is closed at one end. At its, open end a 0.5 m long uniform string is vibrating in its, second harmonic and it resonates with the fundamental, frequency of the pipe. If the tension in the wire is 50 N and, the speed of sound is 320 ms~, the mass of the string is, , (a) Sgrams (b) 10 grams 2010), (c) 20grams (d) 40 grams, , In the experiment to determine the speed of sound using, aresonance column, 2007), , (a) prongs of the tuning fork are kept ina vertical plane, (b) prongs of the tuning fork are kept in a horizontal plane, (c) in. ane of the two resonances observed, the length of the, resonating air column is close tothe wavelength of sound in air, (d) in one of the two resonances observed, the length of, the resonating air column is close to half of the, wavelength of sound in air, A massless rod of length 1 is suspended by two identical, strings AB and CD of equal length. A block of mass m is, suspended from point O such that BO is equal to ‘x’. Further it, is observed that the frequency of Ist harmonic in AB is equal to, 2nd harmonic frequency in CD. ‘x" is [2006 - 3M, —1|, iz A KLhdbdhd Y ed, @ Fs, 4L, (b) 3, (c) a B, L +x, , @ 4 m, , An open pipe is in resonance in 2nd harmonic with, frequency f,. Now one end of the tube is closed and, frequency is increased to f; such that the resonance again, occurs in nth harmonic. Choose the correct option |2005S|, , 3 5, @) "=3,h=Fh ) "=3,h=5f, 4 4, , , , , , w, , , , , , , , —————=D, , , , , , , , , , , , 3 5, © 75 A=Th @ *=5R=Fh, , Ina resonance tube with tuning fork of frequency 512 Hz,, first resonance occurs at water level equal to 30.3 cm and, second resonance occurs at 63.7 cm. The maximum, , possible error in the speed of sound is 120055], (a) $1.2cm/s (b) 1024 cm/s, (c) 204.8 cm/s (d) 153.6cm/s, , A pipe of length ¢,, closed at one end is kept in a chamber, of gas of density p,. A second pipe open at both ends is, placed in a second chamber of gas of density p,. The, compressibility of both the gases is equal. Calculate the, length of the second pipe if frequency of first overtone in, both the cases is equal [2004S]

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25., , 26,, , 27., , 29., , 4, |e 4 2, (a) $0 (b) 41, fa (c) tf (d) of, , A sonometer wire resonates with a given tuning fork, forming standing waves with five antinodes between the, two bridges when a mass of 9 kg is suspended from the, wire, When this mass is replaced by a mass M, the wire, resonates with the same tuning fork forming three, antinodes for the same positions of the bridges. The value, of Mis 120028 |, (a) 25kg (db) Skg (ce) «125k (d) 1/25 kg, Two vibrating strings of the same material but lengths L, and 2 have radii 2r and respectively. They are stretched, under the same tension. Both the strings vibrate in their, fundamental nodes, the one of length £ with frequency v,, and the other with frequency v.. The raio v,/v, is given, by [20005], (a) 2 (b) 4 () 8 (dt, , An open pipe is suddenly closed at one end with the, result that the frequency of third harmonic of the closed, pipcis found to be higher by 100Hz than the fundamental, frequency of the open pipe. The fundamental frequency, of the open pipe is [1996 - 2 Marks}, (a) 200Hz = (b)_ 300Hz (c) 240Hz = (d) 480, A wave disturbance in a medium is described by, , yao = 0.0200s{ sons +=) ost! Ons) where.x and yare, in metre and t is in second 119955], (a) Anode occursat x =0.15m, , (b) An antinode occurs at x= 0.3 m, , (c) The speed wave is 5 ms!, (4) The wave length is 0.3 m, ‘An object of specific gravity p is hung from a thin steel, wire. The fundamental frequency for transverse standing, waves in the wire is 300 Hz. The object is immersed in, water so that one half of its volume is submerged. The, , new fundamental frequency in Hz is [1995S], , W2 1/2, 2p-I 2», cw m2") = 20 53), 2p-1, , 2p, , @ 20455) @ f°"), , ‘A wave represented by the equation y= a cos (kx — om) is, with another wave to form a stationary wave, , such that point x = 0 is a node. The equation for the other, , wave is 11988 - 1 Mark], , (a) asin (kx + of) (b) - a cos(kx — of), , (c) - a cos (kx + wt) (4) -asin(kx - af), , A cylindrical tube open at both ends, has a fundamental, “f in air. The tube is dipped vertically in air. The, , tube is dipped vertically in water so that half of it is in, , water, The fundamental frequency of the air column in, [1981-2 Marks], , f (b) 5 ©) f @