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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Wavelength of wave is a distance between two particles in phase differing byA. `pi`B. `2pi//3`C. `2pi`D. `pi//3` |
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Answer» Correct Answer - C The phase difference between any two successive crests is `2pi` rad |
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| 202. |
Two particles separated by a distance 16.5 mm in a progressive wave has a phase difference of `3pi//8` rad. If the number of waves passing across a point in the medium in 1s is 3750, then the velocity of wave will beA. 3300 m/sB. 330 cm/sC. 330 m/sD. 1650 m/s |
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Answer» Correct Answer - C `x = 16.5 xx 10^(-3) m` `delta = (2pi x)/(lamda) :. lamda = (2pi x)/(delta) = (2pi xx 16.5 xx 10^(-3))/((3pi)/(8))` `lamda = (8 xx 2 xx 16.5 xx 10^(-3))/(3)` `v = n lamda = (3750 xx 8 xx 2 xx 16.5 xx 10^(-3))/(3)` `= 330 m//s` |
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| 203. |
Wavelength of wave is a distance between two particles in phase differing byA. `pi`B. `2 pi`C. `(2pi)/3`D. `pi/3` |
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Answer» Correct Answer - B At a given time (t = constant) the phase change with position x. Phase change at a given time for a distance `Deltax` is `Deltaphi = (2pi)/(lamda) xx Deltax` As, the distance between two crests is `lamda` For distance `lamda`, the phase change is `Delta phi = (2pi)/(lamda) .lamda = 2pi` |
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| 204. |
Turning fork A of frequency 305 Hz produces 5 beats `s^(-1)` with another turing fork B. After filling tuning fork B, it produces 3 beats `s^(-1)` with A. The frequency of B before filling wasA. 300 HzB. 313 HzC. 310 HzD. 308 Hz |
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Answer» Correct Answer - A The phenomenon of beats is used in the determination of unknown frequencies. Suppose `v_(2)` is the unknown frequency of a tuning fork B. Let this fork B produce m beats per second with another tuning fork A of known frequency `v_(1)`, As number of beats/s is equal to difference in frequency of two sources. Therefore, `v_(2) = v_(1) +- m` When the prong of fork B is filed a little, it becomes lighter and its frequency of vibration increases on sounding the filed fork B with fork A, we count the number of beats `s^(-1)`. Proceeding as, we conclude that, if number of beats `s^(-1)` on filing fork B of unknown frequency increases, m would So, frequency of tuning fork B `= 305 +- 5 = 310 Hz, 300Hz` Since, on filing tuning fork B, number of beats decreases. This means that frequency of B should be less ie, 300 Hz |
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| 205. |
The wavelength of sound from a turning fork of frequency 330 Hz is nearlyA. 100 cmB. 1 cmC. 10 cmD. 330 cm |
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Answer» Correct Answer - A Velocity of sound in air `v=330 ms^(-1)` `lambda=v/n=330/330=1 m =100 cm`. |
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| 206. |
What is the ratio of velocity of sound in hydrogen gas to that in air at NTP? (At NTP the density of hydrogen is `0.0009" gmcc"^(-1)` and that of air `0.001" gmcc"^(-1)`)A. `3/sqrt(10)`B. `sqrt(90)`C. `sqrt(10)/3`D. `1/sqrt(90)` |
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Answer» Correct Answer - C Given, density of hydrogen, `rho_(H)=0.0009" gmcc"^(-1)` density of air, `rho_("air")=0.01" gm cc"^(-1)` `v_(H)/v_("air")=sqrt(rho_("air")/rho_(H))=sqrt(0.001/0.0009)=sqrt(10/9)=sqrt(10)/3` |
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| 207. |
Velocity of sound is maximum inA. waterB. vacuumC. airD. metal |
| Answer» Correct Answer - D | |
| 208. |
Velocity of sound is maximum at NTP inA. hydrogenB. cabondioxideC. oxygenD. nitrogen |
| Answer» Correct Answer - A | |
| 209. |
The bells of a college or a temple are made of large size. It is for :A. producing sound of high-pitchB. producing lound soundC. producing sound of high-qualityD. show |
| Answer» Correct Answer - B | |
| 210. |
The velocity of sound in a gas is directly proportional to the square root of the temperature of the gas taken in degree celsius .A. directly proportional to square root of temperatureB. directly proportional to the temperatureC. inversely proportional to the square root of temperatureD. directly proportional to the square of temperature |
| Answer» Correct Answer - A | |
| 211. |
The voice of a lion is different from that of a mosquito becauseA. the two animals have different sizeB. the two voice travel with different velocitiesC. the sounds have different pitchD. the sound have different phases |
| Answer» Correct Answer - C | |
| 212. |
When a wave of wavelength 3m travels through a medium then two particles separated by the distance of 9m are the particles inA. same phaseB. opposite phaseC. phase `pi//2`D. difference of `6pi//2` |
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Answer» Correct Answer - A Phase diff. `= (2pi x)/(lamda)` |
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| 213. |
The velocity of sound in a gas is proportional toA. square root of isothermal elasticityB. adiabatic elasticityC. square root of adiabatic elasticityD. isothermal elasticity |
| Answer» Correct Answer - C | |
| 214. |
The equation of a travelling wave is, `Y = A sin 2pi (pt-x//5)` Then the ratio of maximum particle velocity to wave velocity is,A. `(piA)/(5)`B. `2sqrt(5pi A)`C. `(2piA)/(5)`D. `(2piA)/(sqrt5)` |
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Answer» Correct Answer - C `omega = 2pi p and k = (2pi)/(5)` `:. n = p and (2pi)/(lamda) = (2pi)/(5)` `(v_("Pm"))/(v) = (A omega)/(n lamda) = (A2pi p)/(p xx 5) = (2pi A)/(5)` |
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| 215. |
Which of the following properties of sound is affected by change in the temperature of air ?A. amplitudeB. frequencyC. wavelengthD. intensity |
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Answer» Correct Answer - B `v = n lamda " " v prop sqrtT` |
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| 216. |
The change in speed of sound in a gas is independent of change isA. density of gasB. temperature of gasC. moisture content of the gasD. wavelength of the sound wave |
| Answer» Correct Answer - D | |
| 217. |
Velocity of sound in air is not affected by change inA. moisture content of airB. temperature of airC. atmospheric pressureD. composition of air |
| Answer» Correct Answer - C | |
| 218. |
The sound is a form of energy which propagates through the medium in the form ofA. transverse wavesB. longitudinal waveC. both, longitudinal and transverseD. electromagnetic waves |
| Answer» Correct Answer - B | |
| 219. |
Velocity of sound is maximum inA. waterB. airC. vaccumD. metal |
| Answer» Correct Answer - D | |
| 220. |
The r.m.s velocity of the molecules of a gas is C and velocity of sound in the gas is V. The relation between V and C isA. `(V)/(C) = (gamma)/(3)`B. `(V)/(C) = 3 gamma`C. `(V)/(C) = sqrt(3 gamma)`D. `(V)/(C) = sqrt((gamma)/(3))` |
| Answer» Correct Answer - D | |
| 221. |
The sound is a form of energy which propagates through the medium in the form ofA. transverse wavesB. both longitudinal and transverse wavesC. longitudinal wavesD. electromagnetic waves |
| Answer» Correct Answer - C | |
| 222. |
If the volume elasticity of fresh water and sea water are assumed to be the same, it is necessary that for the velocity of sound to be the sameA. fresh water must be a hihger temperatureB. sea water must be at a higher temperautreC. both must be at same temperatureD. fresh water must have higher refractive index |
| Answer» Correct Answer - B | |
| 223. |
Which of the following is a mechanical wave?A. radio waveB. X-raysC. light waveD. sound wave |
| Answer» Correct Answer - D | |
| 224. |
A light pointer fixed to one prong of a tuning fork touches gnetly a smoked vertical plate. The fork is set vibrating and the plate is allowed to fall freely. 8 complete oscilllations are counted when the plate falls through 10cm.What is the frequency of the tuning fork?A. 280 HzB. 56 HzC. 560 HzD. 360 Hz |
| Answer» Correct Answer - B | |
| 225. |
The frequency of `A` note is `4` times that of `B` note. The energies of two notes are equal. The amplitude of `b` notes as compared to that of `A` note will beA. doubleB. equalC. four timesD. eight times |
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Answer» Correct Answer - C `E prop omega^(2) A^(2)` or `E prop f^(2) A^(2)` `E` is same `:. fA = "constant"` or `A prop (1)/(f)` |
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| 226. |
Transverse waves are generated in two uniform steel wires `A and B` by attaching their free ends to a fork of frequency `500 Hz`. The diameter of wire `A` is half that `B` and tension in wire `A` is half the tension in wire `B`. What is the ratio of velocities of waves in `A and B`?A. `1:2`B. `sqrt2:1`C. `2:1`D. `1:sqrt2` |
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Answer» Correct Answer - B `v= sqrt((T)/(rhoS))= sqrt ((T)/(rho(pid^(2))//(4)))` `:. v prop sqrt((T)/(d^(2)` |
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| 227. |
both the strings , shown in figure are made of same material and have same cross - section. The pulleys are light the wave speed pf a travsverse wave in the string AB is `v_(1)` and in CD is `v_(2)`. The ratio `v_(1) // v_(2)` is A. 1B. 2C. `sqrt2`D. `1sqrt2` |
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Answer» Correct Answer - D |
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| 228. |
The molecular weighs of oxygen and hydrogen are 32 and 2 respectively. The root mean square velocities of oxygen and hydrogen at `NTP` are in the ratioA. `4 : 1`B. `1 : 4`C. `1 : 1`D. `2 : 1` |
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Answer» Correct Answer - B `v_(1) prop (1)/(sqrt(M_(1))) and v_(2) prop (1)/(sqrtM_(2))` `:. (v_(2))/(v_(1)) = sqrt((M_(1))/(M_(2))) = sqrt((2)/(32)) = (1)/(4)` |
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| 229. |
The phase difference between two particles in a medium separated by a distance x is ` pi //6` .If the frequency of the oscillation is 50 Hz and the velocity of propagation of the wave is 100 m/s then x =A. 1/3 mB. 1/4 mC. 1/6 mD. 1/12 m |
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Answer» Correct Answer - D |
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| 230. |
The phase difference between two particles in a medium separated by a distance x is ` pi //6` .If the frequency of the oscillation is 50 Hz and the velocity of propagation of the wave is 100 m/s then x =A. 1/3 mB. 1/4 mC. 1/6 mD. 1/12m |
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Answer» Correct Answer - C `d = (2pi x)/(lamda)` `x = (delta lamda)/(2pi) = ((pi)/(6) xx (v)/(n))/(2pi) = (1)/(12) xx (100)/(50) = (1)/(6) m` |
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| 231. |
The equation of a wave travelling on a string is dA. `64 cms^(-1)` in -X-directionB. `32 cms^(-1)` in -X-directionC. `32 cms^(-1)` in +X-directionD. `64 cms^(-1)` in +X-direction |
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Answer» Correct Answer - D Given , `y=4 sin (4 pi t -(pi x)/16)` where, `omega=4pi` and `k=pi/16` `:. V=omega/k=(4pi)/(pi/16)=64 cms^(-1)` Negative sign with x in the wave equation shows that the wave is travelling along +x-direction. |
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| 232. |
Of the following, the equation of progressive wave isA. `y=a sin (omega t+kx^(2))^(2)`B. `y = a sin (omega t-kx)`C. `y=a/sqrt(2) sin (omega t^(2)-kx^(2))`D. `y=a/2 sin (omega t^(2)-kx^(2))` |
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Answer» Correct Answer - B The position r for such a wave changes in two dimensional plane with time. Therefore, (b) represents the correct equation. |
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| 233. |
The equation of a wave is given by `y=10 sin ((2pi)/45 t+alpha)`. If the displacement is 5 cm at `t=0`, then the total phase at `t=7.5` s isA. `pi/3`B. `pi/2`C. `pi/6`D. `pi` |
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Answer» Correct Answer - B Given `y=10 sin [(2pi)/45 t+alpha]` `y=5 cm` at `t=0` `:. 5=10 (sin alpha)` or `sin alpha =1/2` or `alpha =pi/6` Again if `t=7.5 s` Then, total phase `=(2pi)/45xx15/2+pi/6=pi/3+pi/6` `=(2 pi +pi)/6=(3pi)/6=pi/2` |
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| 234. |
Velocity of sound wave in air is 330 m/s for a particular sound in air.A path difference of 40 cm is equivalent to a phase difference of 1.6 `pi.` The frewuency of this wave isA. 165 HzB. 150 HzC. 660 HzD. 330 Hz |
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Answer» Correct Answer - C Here, `=330 ms^(-1)` Phase difference `Delta phi =(2pi)/lambda. Delta x` `1.6 pi =(2pi)/lambda 40/100` `:. lambda =0.5 m` i.e. `lambda =50` cm `=0.5 m` `n=v/lambda=330/0.5=660 Hz` |
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| 235. |
The phase difference between two points separated by 0.8 m in a wave of frequency 120 Hz is `90^(@)` . Then the velocity of wave will beA. `720 ms^(-1)`B. `384 ms^(-1)`C. `250 ms^(-1)`D. `1 ms^(-1)` |
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Answer» Correct Answer - B It is given that `v=120` Hz, phase difference, `Delta phi=pi/2` and path difference, `Delta x=0.8 m`. As `Delta phi =(2pi)/lambda . Delta ximplies lambda =(2pi)/(Delta phi). Delta x=(2pi xx 0.8)/(pi//2)=3.2 m` Hence, wave velocity, `v=v lambda =120xx3.2=384 ms^(-1)`. |
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| 236. |
Regarding speed of sound ingas, match the following . |
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Answer» Correct Answer - (a)Q, (b)R, (c )Q,(d)S |
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| 237. |
One end of a string of length L is tied to the ceiling of a lift accelerating upwards with an acceleration 2. The other end o the string is freee. The linear mass density of the string varies linearly from 0 to `lamda` from bottom to top. The acceleration of a wave pulled through out the string is `(pg)/(4)`. Find p. |
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Answer» Correct Answer - 3 |
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| 238. |
[Q.Nos. 1-2] y(x, t) equation of a lingiutudinal wave is given as `y = 10^(-2)2(pi)[1000t+(50)/(17)x]` (All Si units If density of the gas is `10^(-3)kg//m^(3)`, find the pressure amplitubeA. 200.62`N//m^(2)`B. 421.24`N//m^(2)`C. 100.26 `N//m^(2)`D. 21.36 `N//m^(2)` |
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Answer» Correct Answer - D |
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| 239. |
[Q.Nos. 1-2] y(x, t) equation of a lingiutudinal wave is given as `y = 10^(-2)2(pi)[1000t+(50)/(17)x]` (All Si units At t = 0 Change in pressure is maximum at x=……….m.A. 0.34B. 0.255C. 0.085D. All of these |
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Answer» Correct Answer - A |
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| 240. |
om the above problem , shape of the wave at time t = 3 s if . O is a fixed end will beA. B. C. D. |
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Answer» Correct Answer - A |
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| 241. |
Two waves are given by`y_(1) = a sin (omega t - kx)` and `y_(2) = a cos (omega t - kx)`. The phase difference between the two waves isA. `pi//2`B. `pi//8`C. `pi//8`D. `2pi` |
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Answer» Correct Answer - A `y_(1) = A sin (omegat - kx)` `y_(2)= A sin(omega t-kx + (pi)/(2))` `phi_(2) - phi_(1) = omega t - kx + (pi)/(2) - omega t + kx` `= (pi)/(2)` rad |
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| 242. |
In the problem number 130, the wavelength of the wave isA. 1.5 mB. 2 mC. 3 mD. `2pi m` |
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Answer» Correct Answer - C `k = (pi)/(150)` `(2pi)/(lamda) = (pi)/(150)` `lamda = 300 cm = 3m` |
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| 243. |
The equation of a transverse wave is given by `y=10 sin pi (0.01 x -2t )` where x and y are in cm and t is in second. Its frequency isA. `10^(-1) Hz`B. 1HzC. 2HzD. 0.01 Hz |
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Answer» Correct Answer - B `omega = 2pi` `2pi n = 2pi " " :. n = 1` |
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| 244. |
The diameter of an iron wire is 1.20 mm. If the speed of transverse waves in the wire is `50.0m//s`, what is the tension in the wire? The density of iron is `7.7xx10^(3)kg//m^(3)` |
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Answer» Correct Answer - 21.78 N |
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| 245. |
Assertion : Two strins shown in figure have the same tension. Speed of transverse waves in string`-1` will be more. Reason : `v prop (1)/sqrt(mu)`,Here`mu is mass per unit length of string.A. If both Assertion and Reason are true and the Reason is correct expanation of the Assertion.B. If both Assertion and Reason are true but the Reason is not correct expanation of the Assertion.C. If Assertion is true, but the Reason is false.D. If Assertion is false but the Reason is true. |
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Answer» Correct Answer - D Just by observation we cannot say that `mu_(2) gt mu_(1)` and hence `v_(2) gt v_(1)`. If their densities are different, then `mu_(2)` may be less then `mu_(1)` also. |
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| 246. |
Asserton: `y-x` graph of a transverse wave on a string is as shown in figuer. At potential energy and kinetic energy both are minimum. Reason : At point `B` kinetic energy and ptential energy both are maximum. A. If both Assertion and Reason are true and the Reason is correct expanation of the Assertion.B. If both Assertion and Reason are true but the Reason is not correct expanation of the Assertion.C. If Assertion is true, but the Reason is false.D. If Assertion is false but the Reason is true. |
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Answer» Correct Answer - B At mean positive kinetic energy is maximum and there is maximum stretch in string. Because one side particles are moving up and the other side particles are moving down. Hence, potential energy is also maximum. |
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| 247. |
Which of the following voice have and greater pitch ?A. maleB. femaleC. mosquitoD. tiger |
| Answer» Correct Answer - C | |
| 248. |
What name is given to sound waves of frequencies higher than 20 kHz?A. Infrasonic wavesB. Ultrasonic wavesC. Audible wavesD. Supersonic waves |
| Answer» Correct Answer - B | |
| 249. |
The minimum distance between two particles similar phase is 10 cm. The time after which given particle comes to same phase is 0.05 second. What is the velocity of progressive wave ?A. 2000 cm/sB. 200 cm/sC. 100 cm/sD. 50 cm/s |
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Answer» Correct Answer - B `v = (lamda)/(T) = (10)/(0.05) = (1000)/(5) = 200` |
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| 250. |
What would be the wavelength of a sound wave in iron ? V = 4950 m/s. If its wavelength was 1.4 m in air in which its speed was 330 m/sA. 0.29 mB. 17 mC. 21 mD. 18 m |
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Answer» Correct Answer - C `(lamda_(2))/(lamda_(1)) = (v_(2))/(v_(1))` `:. lamda_(2) = (v_(2))/(v_(1)) lamda_(1) = (4950 xx 1.4)/(330) = 21m` |
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