Waves Questions and Answers

In YDSE interference pattern produced by two identical slits the intensity at the site of the central maximum is I The intensity at the same spot when either of two slits is closed is 3 21 4 I 1 1 2 2 1 4

31 A transverse wave is expressed by the equation y 10 sin 2n 0 1 sec The wavelength of the wave is B 100 cm 100 2 C A 10 cm 32 The coordinates of a moving particle at an arbitrary time t are given by x ct and y bt where c and X 100 cm where x is in cm and t is in D 1000 cm

A stretched wire of length 114 cm is divided into three segments whose frequencies are in the ratio 1 3 4 the length of the segments must be in the ratio 18 24 72 O 12 16 48 04 3 12 O 12 4 3

The number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are velocity of sound 340 ms AIPMT 2014 1 4 3 7 2 5 4 6 S

Question No 21 Phy Section A This section contains 35 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 and 4 out of which only one is correct An object in simple harmonic motion takes 0 250 second to move from its equilibrium position to its maximum displacement y 5 cm The maximum velocity of the object is y 5 cm y 0 y 5 cm 1 0 25s 5m cm s O 10 cm s 25 cm s O101 cm s

Transverse waves are possible in solids only because 1 They can sustain to compressive stress 2 They can sustain to longitudinal stress 3 They can sustain to shearing stress 4 They cannot sustain to shearing stress

A transverse wave is travelling along a string from left to right The figure below represents the shape of the string at a given instant At this instant among the following choose the wrong statement i ard ari qfarila i varia fa fa REGUL pre A Points D E F have upward positive velocity fa D E F HER IN I B Points A B and H have downward negative velocity BH an C Point C and G have zero velocity D Points A and E have minimum velocity Your Answer

ong answer Please clarify what is wrong in my solution 12 A black body is at a temperature of 5760 K The energy of radiation emitted by the body at wavelength 250 nm is U at wavelength 500 nm is U and that at 1000 nm is U Wien s constant b 2 88 x 106 nmK Which of the following is correct NEET 2016 1 U U 3 U 0 12 Amd Wier s law U TA Stefam law DUA fade Allerding to it Uj y 500mm 2 U 0 4 U U 1 1 3 The power radiated by a black body is P and it radiates maximum energy at wavelength 2 If the temperature of the black body is now changed so that it radiates maximum energy at wavelength 320 o the power radiated by it becomes nP The 4 value of n is NEET 2018 250mm 2 4

An object of mass m is attached to a spring of spring constant k and moves on a frictionless horizontal surface The mass is at X 0 where the spring is unstretched and it has an initial velocity of Vo in the positive X direction as shown Find the average velocity between t 0 and t T 3 where T is the period of oscillation of the mass on the spring Spring uncompressed O O 3Vo sin 2T 3V0 sin 2T 2T 2T 3 Ovo sin 2 C 2T sin 13 m X 0 V

Question No 37 The two waves having intensities in the ratio 1 9 produce interference The ratio of the maximum to the minimum intensities is equal to O 81 1 O 3 1

A uniform string of length L and mass m is fixed at both ends under tension T then it can vibrate with frequency given by f O f f 3 IT 2mL 1 LLE 2Lm 7 T 24m

The intensity of sound reduces by 20 on passing through a glass slab If sound of intensity is made to cross through two such slabs then the intensit of emergent sound will be 1 0 36 3 0 4 2 0 64 4 0 8

A source of sound produces waves of wavelength 0 80 m in air The same source of sound produces waves of wavelength 4 0 m in water If the velocity of sound in air 332 ms then velocity of sound in water is A O 1660 ms 1 B O 1640 ms 1 C O 1650 ms D O 1600 ms 1 1

energy Q No 6 View In English A string of mass 0 2 kg and length 2m is tied at two ends to fixed supports under a tension of 10 N A point P on the string is found to travel from one extreme to other in Taking one end as x 0 and the other end x 2 m and t 0 as the time when P is at rest Position of P is x The correct statements will be 1 2 3 4 Correct Answer 3 4 Your Answer 1 Your Status Incorrect For 0 1 0 1s energy flows across P in positive x direction for 0 x 1m For 0 t 0 05 s energy flows across P in negative x direction for 0 x 1m At t 0 05 s rate of energy flow through P is zero for x 0 5 m At t 0 1s rate of energy flow through P for all values of x is zero

7 The frequency changes by 10 as the source approaches a stationary observer with constant speed us What would be the percentage change in frequency as the source recedes the observer with the same speed Given that vs v v speed of sound in air negro go to Aiscal soubom a 14 3 baiduob sqiq b 20 c 16 7 d 10

14 An open pipe of sufficient length is dipping in water with a speed u vertically If at any instant I is length of tube above water Then the rate at which fundamental frequency of pipe changes is speed of sound c a cv 2 c c 2v 2 11 BIL V b cv 4 d c 4v 2 32

7 3 3 14 13 Identical wires A and B of different materials are hung from the ceiling of a room The density of wire A is greater than the density of wire B but their lengths are same Identical wave pulses are produced at the bottom of respective wires The time taken by the pulse to reach the top is a greater for wire A b greater for wire B c same for both the wires d cannot be determined es

15 A 10 W source of sound of frequency 1000 Hz sends out waves in air The displacement amplitude at a distance of 10 m from the source is speed of sound in air 340 m s and density of air 1 29 kg m a 0 62 m c 1 6 m b 4 2 m d 0 96 m

17 A wave pulse on a string has the dimension shown in figure The wave speed is v 1 cm s If point Ois a free end The shape of wave at time t 3 sis V 1 cm s a c 1 cm 1cm 1cm1cm 2cm b 1cm d K OG 1cm 1cm 1cm O 2cm

16 The amplitude of a wave disturbance propagating in positive x axis is given by y at t 0 and y 1 1 x 1 1 1 x 2 at t 2 s where x and y are in metres The shape of the disturbance does not change during the propagation The velocity of the wave is a 1 m s c 2 m s b 0 5 m s d 4 m s

8 When a source of sound of frequency f crosses a stationary observer with a speed us speed of sound v the apparent change in frequency Af is given by 2f Vs a b 2fv Vs fVs c V 2f v Vs d

r 10 A transverse wave y 0 05sin 20nx 50nt in metres is propagating along ve X axis on a string A light insect starts crawling on the string with a velocity of 5 cm s at t 0 along the ve X axis from a point where x 5 cm After 5 s the difference in the phase of its position is equal to a 150T c 245T b 250T d 5T

3 In an experiment it was found that string vibrates in n loops when a mass M is placed on the pan What mass should be placed on the pan to make it vibrate in 2 n loops with same frequency Neglect the mass of pan a 2M M 4 b c 4M d M 2

In given diagram calculate value of x for which intensity at point P is equal to intensity at point O S and S are coherent sources O 3D O2D 0 20 OV3D D Screen

A standing wave having 3 nodes and 2 antinodes is formed between two atoms having a distance 1 21 between them The wavelength of the standing wave is 1 1 21 2 2 42 3 6 05

The length of the string of a musical instrument is 90 cm and has a fundamental frequency of 120 Hz Where should it be pressed to produce fundamental NEET 2020 Phase 2 frequency of 180 Hz 1 80 cm 2 75 cm 3 60 cm 4 45 cm

E B C The electric field associated with an em wave in vacuum is given by E 140 cos kz 6 x 108t where E z and t are in volt m meter and seconds respectively The value of wave vector k is a 2 m c 6 m b 0 5 m d 3 m

A transparent cylinder has its right half polished so as to act as a mirror A paraxial light ray is incident from left that is parallel to principal axis exits parallel to the incident ray as shown The refractive index n of the material of the cylinder is de and a la stato a fare Froend dardan OPTIONS MARK FOR REVIEW fami CLEAR SELECTION

Y 0 37 sinx 9x 1001 and y2 0 37 sin a 9x 100t n 9 where y V2 and x are in meters and it is in seconds When these two waves are combined a traveling wave is produced What are a amplitude b wave speed and c wavelength of that traveling wave a Number b Number i Units Units m m s

8 A transverse wave in x y plane along positive x axis at t 0 is represented as YA A B X C A B C and D are four particles of the medium Which of the particles has velocity in positive y direction at t 0 1 A 3 C 2 B 4 D

A string of mass 1kg length 1m connected to a block of mass 2kg Block is pulled by a force of 6N There is no friction anywhere A pulse is generated at rear end A of string Then 2kg B 6N A Time taken by pulse to reach from A to B is 2 sec B Motion of pulse is non uniformly accelerated w r t ground frame of reference C Time taken by pulse to move from A to B and then from B to A are equal

In Young s double slit experiment the phase difference between two waves reaching at a point is 3 The intensity of this poin expressed as a fraction of maximun intensity lo is NCERT Pg 364 1 3 3 10 10 2 4 1 2

A loud speaker L is placed in long narrow hall with two doors D and D open to the very long playground as shown in figure The distance D D is 12 m distance between two parallel walls of hall is 9 m The loud speaker is fitted to the wall on a line perpendicular to D D which passes through door D On same line one interference maxima is obtained at P at distance 9 m from door D It is known that loud speaker emits single frequency sound of frequency 150 Hz and because of presence of some other gas in hall and bit high temperature speed of sound waves in hall is 450 m s while in air in ground is 300 m s Hall 9m D Play ground P Q Close to P next interference maximum at Q is obtained if PQ 7 m Just in front of door D an interference minimum will be obtained On line joining L D 2 P and Q maximum six interference minima will be obtained

9 An ideal gas in a container of dimension 1 If v is velocity of a molecule of the gas the colliding frequency on the wall of container is 1 2 2 31 V

8 Two tuning forks A and B made of same material are slightly out of tune and produce beats of frequency 7 Hz When B is slightly filed the beat frequency increases to 9 Hz If the frequency of A is 274 Hz the original frequency of B was 1 524 Hz 2 268 Hz 3 281 Hz 4 312 Hz

The figures represent two snaps of a travelling wave on a string of mass per unit length 0 25 kg m The two snaps are taken at time t 0 and at t 1 24 s Then the possible solution for wave are y mm 10f 5 5 10 Figure 1 t 0 x m speed of wave is 4 m s the tension in the string is 4 N y mm 10 5 h 1 x m 5 Figure 2 1 0 10 the equation of the wave is y 10 sin x 4 t 6 the maximum velocity of the particle 25 m s IL 60

In a string transverse wave speed is 100 m s and frequency is 500 Hz and amplitude is 2 x 10 2 m Its wave equation is Y 2 x 10 sin 1000t 2X A B C D Y 2 x 10 2 sin 1000 t 10zx Y 2 x 10 2 sin 500 t x Y 2 x 10 2 sin 200 t 10x

A tuning fork of known frequency is held at the open end of a long tube which is dipped into water Th tuning fork of frequency 165 Hz resonates for the first time when air columns have lengt 50 0 5 cm and for second time when air columns have length 150 0 1 cm If the speed sound in air is 330 a 0 99 m s then the value of a is

5 For the same objective what is the ratio of the least separation between two points to be distinguished by a microscope for light of 5000 A and electrons accelerated through 100 V used as an illuminating substance a 3075 c 4075 b 3575 d 5075 76 A telescope is used to resolve two stars separated length of light used is

Sound waves travel at 350 m s through a warm air and at 3500 m s through brass The wavelength of a 700 Hz acoustic wave as it enters brass from warm air AIPMT Prelims 2011 1 Decreases by a factor 20 2 Decreases by a factor 10 3 Increases by a factor 20 4 Increases by a factor 10

In a two slit experiment with monochromatic light fringes are obtained on a screen placed at some distance from the plane of slits If the screen is moved by 5 x 10 m towards the slits the change in fringe width is 3 x 10 m If the distance between slits is 10 m the wavelength of light will be a 3000 A c 6000 A b 4000 A d 7000 A

mn 36 Young s experiment is performed with light of wavelength 6000 A wherein 16 fringes occupy a certain region on the screen If 24 fringes occupy the same region with another light of wavelength A then is a 6000 c 5000 b 4500 d 4000

a 0 174 nm c 0 174 m d 0 174 x 10 m 54 In a Young s double slit experiment let S and S be the two slits and C be the centre of the screen If ZS CS 0 and is the wavelength the fringe width will be a c 0 b 20 d 2 20

24 180 The minimum phase difference between minima of displacement wave and minima of pressure wave in the propagation of longitudinal wave is Zero EIN T 3x Solution Answer 2 P Pocos wt kx for minima wt kx E O

The a c wavelength of light used in the experiment is 6 x 10 m b 3 x 10 m d 5 x 10 m 1 5 x 107 m 31 The slits in Young s double slit experiment are illuminated by light of wavelength 6000 If the path difference at the central bright fringe is zero what is the path difference for light from the slits at the fourth bright fringe a 2 4 x 10 m c 10 m b d 1 2 x 10 m 0 5 x 10 m

mtG Objective NCERT P 32 In a double slit experiment the distance between the slits is d The screen is at a distance D from the slits If a bright fringe is formed opposite t the slits its a HR b 2 dD c D 2nd d

d conservation of energy does not hold good Two slits are made one millimeter apart and the screen is placed one metre away The fringe separation when blue green light of wavelength 500 nm is used is a 5x10 m c 2x 10 m b 2 5x 10 m d 10 x 10 m a 0 5 b 0 c 0 d on 46 Interfe doubl 5000

which is stretched over a sonometer The bridge of the sonometer is 40 cm apart when the wire is in unison with a tuning fork of frequency 256 When the stone is completely immersed in water the length between the bridges is 22 cm for re establishing same mode unison with the same tuning fork The specific gravity

34 Frequency of oscillation of a body is 5 Hz when a force F is applied and 12 Hz when another force F is applied If both forces F and F are applied together then frequency of oscillation of the body will be a 13 Hz b 169 Hz c 62 Hz d 52 Hz

a Progressive of wave 3 Which of the following equations represents a transverse wave travelling along y axis 1 x A sin wt ky 3 y A sin wt kx 2 x A sin wt ky 4 y A sin wt kx