Waves Questions and Answers

3 Mary is sitting in her parked car with the driver window opened The temperature outside is 12 C A train passes Mary s car as it sounds its whistle at a 112 Hz She hears a sound with a frequency of 104 3 Hz after the train has passed her What speed is the train moving at

2 The attached diagram shows two waves A and B over a one second timeframe From these two waves shown answer the following a How do the frequencies of the two waves compare b How do the wavelengths of the two waves compare c How do the amplitudes of the two waves compare d Where do both the waves share a node Show this by drawing your answer on both diagrams A B

A lab team was collecting data on the amplitude and energy of a mechanical wave as shown in the data table They forgot to record one data point Analyze the data to identify the mathematical relationship between amplitude and energy Calculate the missing data point Amplitude 6 units 7 units 8 units 9 units 10 units Energy 72 units units 128 units 162 units 200 units

Standing wave vibrations are set up in a crystal goblet with four nodes and four antinodes equally spaced around the 15 0 cm circumference of its rim If transverse waves move around the glass at 940 m s an opera singer would have to produce a high harmonic with what frequency in order to shatter the glass with a resonant vibration kHz

A pipe has a length of 0 941 m and is open at both ends Take the speed of sound to be v 343 m s HINT a Calculate the two lowest harmonics of the pipe in Hz Enter your answers from smallest to largest Hz Hz b Calculate the two lowest harmonics in Hz after one end of the pipe is closed Enter your answers from smallest to largest Hz Hz

POSSIBLE POINTS 12 The safety council would like you to compare the characteristics of an earthquake produced tsunami wave and a wind generated surface wave They have decided to compare velocity wavelength frequency and period of the waves in open water before they reach land Use the data given to answer the following questions about the waves Calculate the missing values Show your work in the space below v m s Wave Type Tsunami Wind Generated a 12 5 m 160 000 150 b C f Hz d t s 720

11C a What is dispersion Explain why it happens b When sunlight hits the thin film of a soap bubble only red and green colors seem to be reflected Why is this What happened to the other colors

The transition from the state n 4 to n a hydrogen like atom results in ultraviolet radiation Infrared radiation will be obtained in the transition A 2 1 CO B 3 2 C4 2 3 in D 5 4 Correct Answer

The time period of oscillation of a simple pendulum is The measured value of L is 10 0 cm with an T 2 g instrument having least count 1 mm and time of 100 oscillations of the pendulum is measured to be 125 s using a stop watch of least count 1 s The maximum percentage error in the determination of g is 1 4 2 6 2

Q 177 A bird is moving vertically downward with speed 12 m s What will be the apparent speed of the bird as seen by a fish in water vertically below the bird Refractive indices of respectively air and water are 1 and 1 16 m s 3 9 m s 2 12 m s 4 6 m s Q 177 as fafar 12 m s f se fera fafter a dare furft fer pas street are ar 1 T 1 16 m s 3 9 m s farfer argaren o 81 2 12 m s 4 6 m s

c A convex lens of focal length 20 cm is placed after a slit of width 0 6 mm If a plane wave of wavelength 600 nm falls normally on the slit calculate the linear width of central maximum on the screen Also calculate the linear separation between second order secondary maxima and first order minima 3x2 6 marks CO3

he amplitude of a wave disturbance propagating in positive direction of x 1 1 x re in meters The shape of the wave disturbance does not change during propagation The velocity of the wave is A B 0 5 ms Correct Answer 2 0 ms 1 1 0 ms 1 1 axis is given by y at t 0 and by y 1 1 x 1 at t 2 s where x and y

A stone is dropped in a liquid at rest in a tank The fig a below shows circular wave fonts waves produced at the centre of a circular ripple tank Two corks A and B floats on the water moves up down on the surface as the wave passes The wavelength of the wave is 8 0cm The Fig b shows how the displacement of A varies with time ii iii iv 8 0cm cork A a b c d cork B a 1 Name the type of waves produced on watersurface Longitudinalwave a c Soundwave 2 Displacement mm What is the frequency of thewave a 4Hz b 0 4Hz 2 0 25 0 50 b d b 0 75 1 00 1 25 time s EMwave What is the amplitude of the vibrations of A as wavepasses a 2mm b 0 25mm c 0 50mm d 8mm The horizontal distance between A and B is half the wavelength of the wave Then the displacement of B with timeis same as that of A with equalmagnitude opposite to that of A with equalmagnitude double in magnitude as that ofA half in magnitude as that ofA Transversewave c 2Hz d 0 2Hz v If the distance between the centre of the ripple tank and its edge is 40 cm Then the tin taken by the wave to travel from the centre of the tank to the edgeis a 5s b 2 5s

NEET PHYSICS All India Major Test Series Phase l II Major Test 29 23 09 06 2020 Q 169 The equation of a plane progressive wave is Q 169 Y 3 sinnt 10 When it is reflected at rigid support its amplitude becomes 1 3rd of its previous value The equation of the reflected wave is 1 Y 2 sin x t 5 10 2 Y sin t 3 Y sin x 4 Y sin m 2 10 Y 3 sin n 1 F 3 a fare una 8 1 Y 2 sin 2 Y sin 3 Y sin n XO rafa a gen verafete 4 Y sin a t Metical Exams

The total number of harmonics audible to a person having normal hearing if the length of the open pipe is 17cm and velocity of sound in air is 340 m s is Given Audible range 20Hz to 20000Hz A 16 J

The displacement y in cm produced by a simple harmonic wave is given by y 10 TT sin TX 2000nt The period and maximum velocity of the particles in the medium respectively will be 17 given by B D 10 3s and 330 m s 10 4 s and 200 m s 10 3 s and 200 m s 10 4 s and 330 m s 2 X M

ASRI CHAITANYA IT In case of superposition of waves at x 0 y 2 sin 1026 t y 2 sin 1014 t A the frequency of resulting wave is 510 Hz B the amplitude of resulting wave varies at frequency 3 Hz C the frequency of beats is 6Hz D the amplitude of resulting wave varies at frequency 6 Hz

1 A wave is represented by y A sin Bt Cx where A amplitude B and C are constants then ABC represent to 1 Time 2 Frequency 3 Length 4 All of these CAREE Q 51 a min y A sin Bt Cx ERI afera 8 61A 31414 BC ABC veftia 1 2 3gferat 3 4

11 Two superimposing waves are represented by equation y 2 sin 2 10t 0 4x and y 4 sin 2 20t 0 8x The ratio of Imax to Imin is Sinc sin D 1 36 4 3 1 4 A wave represented by the equation y acorffor 5 2 25 9 4 4 1 2

A signal of form y x 1 x 1 x y cm propagates horizontally from the origin to the right with speed 6 cm s Draw a figure showing the position and the form of this signal at t 0 5 s Explain

32 Two waves get superposed on a string Y 3 sin2 x 10f and y 3 sin2 x 10t Then find the distance between two adjacent nodes on the string sinct sinD 1 25 cm 3 75 cm 2 50 cm 4 100 cm 3 9

When monochromatic light falls normally on the surface of the soap film in air the intensity of the reflected light depends on the wavelength it has a maximum at A 630nm and the minimum at X 525 nm What can be the film thickness Refractive index of the film n 4 3 O 590 625 nm O 640 nm 562 625 nm

Consider a rope fixed at both ends under tension so that it is horizontal i e assume the rope is along x axis with gravity acting along z axis Now the right end is continually oscillated at high frequency v say v 100 Hz horizontally and in a direction along the rope amplitude of oscillation is negligible The oscillation travells along the rope and is reflected at the left end Let the total length of rope be 1 total mass be m and the acceleration due to gravity be g After initial phase say a mintue or so the rope has BLANK 1 wave which is BLANK 2 in nature It results from superposition of left travelling and right travelling BLANK 3 waves This resulting wave has a frequency that of oscillation frequency nu Simple dimensional analysis indicates that the frequency of can be of the form BLANK 5 BLANK 4 A BLANK 1 travelling oscillating stationary regular B BLANK 2 transverse longitudinal regular irregular C BLANK 3 transverse longitudinal regular irregular D BLANK 4 equal to half double independent from E BLANK 5 sqrt g 1 sqrt m g sqrt mgl sqrt 1 g Diwali and Id festivities

wo particles of medium disturbed by the wave propagation are at x isplacements in cm of the particles can be given by the equations y 2sin3xt y 2sin 3xt x 8 The wave speed is A 16 cm sec B 24 cm sec C 12 cm sec D 8

6 Time period of a particle executing SHM is 16 At time t 2 s it crosses the mean position It amplitude of motion is 32 2m Its velocity at t sec is 1 4 m s 2 8 m s 3 1 m s TT

The wave function of a triangular wave pulse is defined by the relation below at time t 0 for 0 x a 2 for a 2 x a 0 every wher else mx y m x a A A YA Direction of pulse propagation X The wave pulse is moving in the X direction in a string having tension T and mass per unit le The total kinetic energy present with the wave pulse is Assume m 1 m Ta B m Ta 2 3m Ta 2 D None of these

Two coherent sources of light of wavelength 6 2x10 6 m produce interfearence The path difference corresponding to 10th order maximum NCERT XII II 363 1 6 2 10 m 2 3 1x10 m 3 1 5x10 m 4 6 2x10 5 m

correct Question Type Single Correct Type 1 2 IS In YDSE and single slit diffraction spherical wavefront is used In YDSE plane wavefront and in single slit spherical wavefront are used In YDSE spherical wavefront and in 3 single slit diffraction plane wavefront is used In YDSE and single slit diffraction plane

Consider an electromagnetic wave propagating in vacuum Choose the correct statement skipped B C D For an electromagnetic wave propagating in x direction the electric field is E 1 1 the magnetic field is B B x t 2 For an electromagnetic wave propagating in x direction the electric field is 1 28 2 and the magnetic field is B B v f 5 Jury For an electromagnetic wave propagating in y direction the electric field is E 1 magnetic field is B B x 1 2 E x1 y 2 and E E 1 E xt and the 5 For an electromagnetic wave propagating in y direction the electric field is E E x and the magnetic field is B B x 1 QUE 1 6 Con MY P S

The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about 150 N C directed inward towards the center of the Earth This gives the total net surface charge carried by the Earth to be Given 8 85 x 10 2 C N m R 6 37 x 10 m A 670 kC Sm E 1 6 Co MY

A sound wave is traveling along positive x direction Displacement y of different particles axis from their mean positions at a given time is shown in the figure po R I I A Particle located at S has zero velocity B Particle located at T has its velocity in the negative direction C Excess pressure at S is zero D Particles located near R are under compression

4 An electromagnetic wave in vacuum has the electric and magnetic fields E and B which are always perpendicular to each other The direction of polarisation is given by X and that of wave propagation by k Then a X B and X BXE b X E and k Ex B c X B and k Ex B d X II E and k II Bx E

Q 6 Two Sources S and S of intensity I and 12 are in front of a screen Fig a The pattern of intensity distribution seen in the central portion is given by Fig b S S a 1 a b c 2 a b d 3 b c d mm b In this case which of the following statements are true a Siand S have the same intensities b Siand S2 have a constant phase difference c Sand S have the same phase d Siand Se have the same wavelength Show All w

5 The equation of a plane progressive wave is t where x 10 18 and y are in cm and f is in second Now which of the following is true 1 Wave velocity is 1 8 cm s 2 Natural frequency is 0 1 cps 3 Wavelength is 0 18 m 4 All of these given by y 5sin 2x

2 6 A particle is oscillating according to the equation X 7cos 0 5 mt where t is in second The point moves from the position of equilibrium to maximum displacement in time 1 4 0 second Smet 3 1 0 second 2 2 second 4 0 5 second

Statement 1 On viewing the clear blue portion of the sky through a Calcite Crystal the intensity of transmitted light varies as the crystal is rotated Statement 2 The light coming from the sky is polarized due to scattering of sun light by particles in the atmosphere The scattering is largest for blue light AIEEE 2011 1 Statement 1 is true statement 2 is false 2 Statement 1 is true statement 2 is true statement 2 is the correct explanation of statment 1 3 Statement 1 is true statement 2 is true statement 2 is not the correct explanation of statement 1 4 Statement I is false statement 2 is true

A source emit sound waves of frequency 1000 Hz The source moves to the right with a speed 32 m s relative to ground On the right a reflecting surface moves towards left with a speed 64 m s relative to ground The speed of sound in air is 332 m s A wavelength of sound in ahead of source is 0 3 m B number of waves arriving per second which meets the reflected surface is 1320 2 e speed of reflected wave is 268 m s D wavelength of reflected waves is nearly 0 2 m

An air column in a pipe closed at one end is made to vibrate in its second overtone by a tuning fork of frequency 440 Hz The speed of sound wave in air is 330 m s End corrections may be neglected Let P denote the mean pressure at any point in the pipe and AP the maximum amplitude of pressure variation Then 15 A length of the pipe is m 16 9 B length of the pipe is m 16 0 C the maximum pressure at the open end is Po D the minimum pressure at the open end is P

22 23 24 25 26 27 28 29 30 31 32 English Review Q The conduction current is the same as displacement current when source is Question Type Single Correct Type 1 ac only 2 de only 3 both ac and de neither dc nor ac

The vibration of a string fixed at both ends are described by Y 2 sin x sin 100st where Y is in mm x is in cm t in sec then A Maximum displacement of the particle at x 1 6 cm would be 1 mm B Velocity of the particle at x 1 6 cm at time t 1 600 sec will be 157 3 mm s Testy m 0 C If the length of the string be 10 cm number of loop in it would be 5 D None of these

A wave propagates in a string in the positive x direction with velocity v The shape a the string at t to is given by 2 Then the wave equation at any instant t is given by f x to A sin O No g x t A sin g x t A sin g x t A sin g x t A sin x v t to q x v t to a x v t to q x v t to

boundary 26 In the standing wave shown particles at the positions A and B have a phase difference of 1 0 5m KIN 3 h Tower 8 Pusa Road New Delhi 110005 Ph 011 47623456

3 1 2 4 1 4 10 A pulse is generated at lower end of a hanging rope of uniform density and length L The speed of the pulse when it reaches the mid point of rope is 1 2gL 2 gL

Equation of a plane progressive wave is given by y 0 6sin 2 t On reflection from a denser medium its amplitude rd 2 3 wave The equation of reflected wave is becomes of the amplitude of incident 1 y 0 6 sin 2m NCERT XI Pg 3791 X 0 4sin2 t 2 3 y 0 4sin2x 1 2

Some examples of wave motion are given the following options In which case was motion is a combination of both transver and longitudinal waves INCERT XI Pg 37 1 Motion of a kink in a longitudinal sprin produced by displacing one end of th spring side ways 2 Waves produced in a cylinder containin a liquid by moving its piston back an forth 3 Waves produced by a motorboat sailin in water 4 Both 1 and 3

3 85 4 245 38 A closed pipe of length 10 cm has its fundamental frequency half that of the second overtone of an open pipe The length of the open pipe 1 10 cm 2 20 cm 3 30 cm 4 40 cm

4 Same speed at same instant 30 Two waves are represented by y 5 sin 2n 75f 0 25x y 10 sin 2n 150t 0 50x 4 The intensity ratio 12 1 1 2 2 1 4 of the two waves in

equal he Waves 187 46 A tuning fork and an air column whose temperature

4x Shape of interference fringes formed on the screen due to point source P in the case shown here P Point source Plane mirror 1 Parabolic 3 Circular y 4 All of these screen 2 Elliptical 4 Hyperbolic Young s double slit experiment is performed with monochromatic light A thin film is introduced in OT 1 10 mm 3 10 pm Slit widths in a Young in the ratio 9 4 R that at maxima is 1 4 9 3 1 25 m Oil floating on interference of lig magnitude of the this effect may b 1 10 6 m 3 10 10 m When white lic of thickness 1 the wavelen reflected sys NOME

B A C A D A Column l HL e Two strings each of length and linear mass density u and 9u are joined together and system is oscillated such that joint P is node T is tension in the strings A and B are fixed ends A B l 9 9 P Two strings each of length and linear mass density and 9 are joined together and system is oscillated such that joint P is antinode T is tension in each string A and B are fixed ends P l 12 P B l P is the mid point of the string fixed at both ends T is tension in the string and u is its linear mass density 12 B B T is the tension in the string fixed at A and B is free end P is mid point u is its the linear mass density Column II p Speed of component travelling wave is portion AP will be q Speed of component travelling wave in the portion AP will be more than that in portion BP r Frequency of oscillation of the system AB can 1 2l be be s Frequency of oscillation of the system AB can 1 T 4l Vu t Wavelength of the wave in the portion PB can 20