Waves Questions and Answers

14 The displacement of a particle executing periodic motion is given as y 4 sin 1000f cos t This displacement equation may be considered as superposition of 1 Two waves 3 Four waves 2 Three waves 4 Five waves

1 Standing waves can not be produced 1 In a string clamped at both ends 2 In a string clamped at one end and free at other end 3 When incident wave sets reflected from the wall super impose 4 When two identical waves with a phase difference of are moving in the same direction super impose

A parallel beam of electrons of a given momentum pass through a screen S containing a slit and then produces a diffraction pattern on a screen S placed behind it The width of the central maximum observed on the screen S can be increased by 2 a decreasing the distance between the screens S and S b increasing the width of the slit in screen S c decreasing the momentum of the electrons d increasing the momentum of the electrons

11 Two coherent sources of different intensities send waves which interfere The ratio of maximum intensity to the minimum intensity is 25 The intensities of the sources are in the ratio 1 25 1 3 9 4 2 5 1 4 625 1

O If the distance between successive compressions and rarefaction in a sound wave is 2 m and R velocity of sound is 360 m s then the frequency is 180 Hz 2 45 Hz 3 120 Hz 4 90 Hz A 2m V 360m 6 DEX 360 hozz

ASSAGE He Ne laser produces light of wavelength 6328 Angstrom at room temperature Choose the correct options Marks The frequency of the emitted radiation OPTIONS 4 74 10 12 Hz 4 74 10 13 Hz

Two coherent waves P and Q meet at a point in phase and superpose Wave P has an amplitude of 1 5 cm and intensity I The resultant intensity at the point where the waves meet is 31 Calculate the amplitude of wave Q 6 09 pr

A string of mass per unit length is clamped at both ends such that one end of the string is at x 0 and the other end at x L When string vibrates in fundamental mode amplitude of the midpoint of string is a and tension in string is F Find the total oscillation energy in J stored in the string Use L 1m F 1 10 N a m 77 x 0 Question Type Numerical Type x L

6 A metal rod of 1 m length is dropped exact vertically on to a hard metal floor Plate capacitor is to be designed it is determined that the impact produces a longitudinal wave of 1 2 kHz frequency The speed of sound in the metal rod is bor 2017 Gujarat a 600 m s c 1800 m s b 2400 m s d 1200 m s

It s for a test Problem A sine wave travels in the positive x direction It has an amplitude of 1 50 cm a speed of 300 m s and a frequency of 200 Hz Determine the angular number of waves

The length of vibrating string is 75 mm and fundamental frequency of vibration is 530 Hz The load applied to string is 1 kg hence mass per unit length of string is CO3 O 0 0155 g cm 1 55 kg cm O 0 155 kg cm O 1 55 g cm

Three consecutive resonant frequencies of stretched string fixed at both ends are 60 Hz 90 Hz and 120 Hz then NCERT Pg 382 1 The fundamental frequency is 30 Hz 2 The given frequencies are 1st 3rd and 5th harmonic 3 The given frequencies are 1st 2nd and 3rd overtone 4 Both 1 and 3 are correct

A trianguler pulse moving at 2cm s on a rope approches an end at which it is free to slide on vertical pole What is the particle speed at the free end at sec from the instant shown 3 4 1cm 1 2cm s 3 3cm s 1cm 2cm s 1cm 1cm 2 1cm s 4 4cm s

Standing waves are produced on a stretched string of length L with fixed ends When there is a node at a distance L 3 from one end then A minimum number of nodes excluding the ends are 2 B next higher number of nodes excluding the ends are 5 C frequency produced may be V 3L D frequency produced may be 3V 2L V velocity of waves in the string

The frequency of tuning fork in resonance tube experiment is 500 Hz The first resonance occured at vibrating length of air column of 17 cm The inner diameter of tube is 3 cm hence velocity of sound in air is CO3 O 35800 m s O 34000 cm s O 34000 m s O 358 m s

The path difference between two waves arriving at a point simultaneously is 38 5 times wavelength of light The CO2 Opoint will be dark Opoint will be bright O point will be sometimes dark sometimes bright nature of point can not be predicted

A simple harmonic progressive wave is represented as Y A sin 2 t nt c cm It the maximum particle velocity is four times the wave velocity then the wavelength of the wave is A B TT A 4 4 A C 2 TA D TT A 2

Two coherent sources of different intensities send waves which interfere If the ratio of maximum and minimum intensity in the interference pattern is 25 then find ratio of intensities of sources 1 25 1 2 5 1 3 4 4 25 16

Two uniform wires of the same material are vibrating under the same tension If the first overtone of the first wire is equal to the second overtone of the second wire and radius of the first wire is twice the radius of the second wire then the ratio of the lengths of the first wire to second wire is MHT CET 2017 A C 133 15 B D 4 1 6

In sonometer experiment the string of length L under tension vibrates in second overtone between two bridges The amplitude of vibration is maximum at MHT CET 2017 L 2L 5L A B LOS C 5 3 3 LLL Pen 3 24 6 6 LLL 2 8 4 2 L L 5L 2 62 6 ww

5 Two tunning forks have frequencies 380 and 384 Hz respectively When they are sounded together they produce 4 beats second After having the maximum sound how long will it take to hear the minimum sound 1 1 second 1 3 second 8 2 4 1 1 16 second second

Two strings A and B of same material are stretched by same tension The radius of the string A is double the radius of string B Transverse wave travels on string A with speed VA and on string B with speed VB The ratic V MHT CET 2016 VB A C 2 is 142 LOB D 1 2 4

A C A simple harmonic progressive wave is represented by y A sin 100 t 3x The distance between two points on the wave at a TU phase difference of radian is 3 T 18 T 3 m m B D MH CET 2010 RIO RO 6 8 m 8

The fundamental frequency of an air column in a pipe closed at one end is 100 Hz If the same pipe is open at both the ends the frequencies produced in Hz are MHT CET 2017 A 100 200 300 400 B 100 300 500 700 200 300 400 500 D 200 400 600 800

ope having mass m hangs vertically from rigid support A transverse wave pulse is produced at the lower end The frequency of wave pulse varies with x from the lower ends as 1 2 3 X X vzJgn Jezi ze gn

A radar sends slow moving a signal of frequency 8 x 10 Hz towards an aircraft approaching the radar If the reflected wave shows frequency shift 2 10 Hz the speed with which the aircraft is approaching the radar is velocity of radar signal is 3 x 108 m s 1 37 5 m s 3 4 m s 2 75 m s 4 85 m s

ed ly 57 A beam of light strikes a piece of glass at an angle of incidence 60 and the refracted beam is completely Beetquestionane polarised The refractive index of the glass is 1 1 5 3 2 nd d 2 3 4 312

A progressive wave is represented by y 12 sin 5t 4x cm On this wave how far away are the two points having phase difference MHT CET 2016 of 90 A EN RO cm cm 2010 B D T cm 4 T 16 cm 0

15 Two coherent waves of intensities I and 41 superpose then the maximum and minimum intensities produced are 1 51 and 31 3 91 and 31 2 91 and I 4 51 and 1

A bird can fly in the air at a constant speed 13 m s There is a wind of speed of 18 km hr blowing from the north The bird has to move in the east west direction What is its speed in m s with respect to the earth 1 5 2 12 3 13 4 18

Numerical A stationary source is emitting sound at a fixed frequency fo which is reflected by two cars approaching the source The difference between t requencies of sound reflected from the cars is 1 2 of fo What is the difference in the speeds of the cars ho The cars are moving at constant speeds much smaller than the speed of sound which is 330 ms at km per hour to the nearest inte m

Two periodic waves of intensities and 2 pass through a region at the same time in the same direction The sum of the maximum and minimum intensities is AIPMT Prelims 2008 1 2 1 2 1 1 3 T4 7 4 2

In Young s double slit experiment the separation d between the slits is 2 mm the wavelength of the light used is 5896 and distance D between the screen and slits is 100 cm It is found that the angular width of the fringes is 0 20 To increase the fringe angular width to 0 21 with same and D the separation between the slits needs to be changed to NEET 2018 1 1 8 mm 3 1 7 mm 2 1 9 mm 4 2 1 mm

Four traveling waves are described by the following equations where all quantities are measured in SI units and y represents the displacement y 0 12 cos 3x 21t y 0 15 sin 6x 42t y 0 13 cos 6x 21t y 0 27 sin 3x 42t Which of these waves have the same period M IV OI and IV and also II and III OI and II and also III and IV They all have different periods O All of them have the same period OI and III and also II and IV

Equation of a longitudinal stationary wave in first overtone mode in a closed organ pipe is y 2 mm sin x cos 2 t Here x is in meter and t in second Match the following List ych dz a 9134 qu f zaz faf f YUMA A T H AH u y 2 mm sin x cos 2 X List I R P Length of pipe Q Wavelength auf S Distance of displacement node from the closed end z Aziz A Distance of first pressure node from the closed end dz 4 a Az z A A B C gus 21 A A A D P 3 Q 3 Q 1 R 4 S 2 Correct Answer P 2 Q 3 R 4 S 1 P 1 Q 3 R 4 S 2 3 Q 4 R 1 S 2 1 List II 4 2 0 m 30 0 5 2 m 1 5 3 m 1 0 m

A cylindrical tube open at both the ends has a fundamental 1 frequency of 390 Hz in air If th of the tube is immersed 260 Hz vertically in water the fundamental frequency of air column will be 310 Hz 620 Hz 415 Hz 4

1 A string vibrate according to the oscillation y 5 sin cos 40 x 1 Where x y are in c m and t is in sec Find the distances between two successive nod and speed of the particle of the string at a position x 1 5 cm when t 9 8 sec

5 Write down the equation for a wave travelling along the negative z direction and having amplitude 0 01 m frequency 550 Hz and Speed 330m s How would the equation change if a wave with the same parameters was travelling along the positive Z direction

For aluminium the bulk modulus of elasticity is 7 6 10 N m and density is 2 7 x 10 kg m The velocity of longitudinal wave in aluminium is 3 6 10 m s O 1 7 x 10 m s O 5 3 x 10 m s 2 4 x 10 m s

7 In Young s double slit experiment the separation d between the slits is 2 mm the wavelength of the light used is 5896 and distance D between the screen and slits is 100 cm It is found that the angular width of the fringes is 0 20 To increase the fringe angular width to 0 21 with same and D the separation between the slits needs to be changed to 1 1 8 mm 21 9 mm 3 2 1 mm 4 1 7 mm

Which of the following colour is scattered most in atmosphere O Red Yellow 01 24 hr min O Indigo

Monochromatic light is refracted from air into the glass of refractive index The ratio of the wavelength of incident and refracted waves is a 1 u c 1 MP PMT 1996 2003 JIPMER 2000 Gujarat 2007 b 1 d 1 1

A cylindrical wave front ABC centred at O symmetric about BE is incident on slits S S BS S O 82 where is wavelength of light used A slab of thickness t and refractive index 4 is placed in front of one of the slits to obtain central maxima at point D symmetrically located with respect to slits If t is least then A B S 37 S O D D E 1 Light emitted by slit S leads with respect to the light emitted by slit S by phase of 2 Light emitted by slit S lags with respect to the light emitted by slit S by phase of 4t

The displacements of two particles executing simple harmonic motion are represented as Y 2sin 10t 8 and y 3cos 10t The phase difference between the velocities of these waves is A B 0 EIN 0 0 1 C

In the given diagram there is a cylindrical can of cross sectional area A and length 0 4m completely filled with liquid of density p It is attached to massless 15 pulley A small hole of area a A is made at the base 100 of can A wave pulse is generated at point A at an instant when small hole is made at base of can When can gets empty the wave pulse reaches point B Then PASI unit is linear 1 find length AB in meter 16 mass density of string AB Neglect mass of can and thrust force due to efflux of liquid

When a tuning fork of frequency 341 is sounded with another tuning fork six beats per second are heard When the second tuning fork is loaded with wax and sounded with the first tuning fork the number of beats is two per second The natural frequency of the second tuning fork is 1 334 2 339 3 343 4 347

A wave whose frequency and amplitude respectively are 100 Hz and 0 01 m is travelling along the string which is stretched with a tension of 50 N If the linear density of the string is 0 5 kg m the rate of transport of wave energy in watt along the string is a 2 b 37 c 57 d10x

2 1 A wire stretched between two rigid supports vibrates in its fundamental mode with a frequency of 45 Hz The mass of the wire is 3 5 10 kg and its linear mass density is 4 0 10 2 kg m What is the speed of a transverse wave on the string 1 1 a 69 m s S b 79 m s 1 c 89 m s S 1 d 99 m s

A wave represented by y 2 sin 3t 4x is reflected from a rarer medium with a loss of 36 of the intensity The equation of the reflected wave is 1 y 1 6 sin 3t 4x 3 y 12 8 sin 3t 4x 2 y 4 y 0 72 sin 3t 4x 1 6 sin 3t 4x

Which of the following two wave equations call form stationary wave NCERT Pg 379 i y Acos wt kx ii y Asin wt kx iii y Asin wt kx iv y Acos wt kx 1 i and ii 3 i and iv 2 iii and iv 4 Both 1 and 2