JEE Main & Advanced Physics Wave Mechanics Question Bank

done Beats Total Questions - 51

• question_answer1)
  Two tuning forks when sounded together produced 4 beats/sec. The frequency of one fork is 256. The number of beats heard increases when the fork of frequency 256 is loaded with wax. The frequency of the other fork is [CPMT 1976; MP PMT 1993]
  A)
             504 done clear
  B)
             520 done clear
  C)
             260 done clear
  D)
             252 done clear
  View Solution play_arrow

• question_answer2)
  Beats are the result of                 [CPMT 1971; J & K CET 2002]
  A)
             Diffraction done clear
  B)
             Destructive interference done clear
  C)
             Constructive and destructive interference done clear
  D)
             Superposition of two waves of nearly equal frequency done clear
  View Solution play_arrow

• question_answer3)
  Two adjacent piano keys are struck simultaneously. The notes emitted by them have frequencies \[{{n}_{1}}\] and \[{{n}_{2}}\]. The number of beats heard per second is [CPMT 1974, 78; CBSE PMT 1993]
  A)
             \[\frac{1}{2}({{n}_{1}}-{{n}_{2}})\]                                  done clear
  B)
             \[\frac{1}{2}({{n}_{1}}+{{n}_{2}})\] done clear
  C)
             \[{{n}_{1}}\tilde{\ }{{n}_{2}}\]                                           done clear
  D)
             \[2\,({{n}_{1}}-{{n}_{2}})\] done clear
  View Solution play_arrow

• question_answer4)
  A tuning fork of frequency 100 when sounded together with another tuning fork of unknown frequency produces 2 beats per second. On loading the tuning fork whose frequency is not known and sounded together with a tuning fork of frequency 100 produces one beat, then the frequency of the other tuning fork is                                       [NCERT 1977]
  A)
             102 done clear
  B)
             98 done clear
  C)
             99   done clear
  D)
             101 done clear
  View Solution play_arrow

• question_answer5)
  A tuning fork sounded together with a tuning fork of frequency 256 emits two beats. On loading the tuning fork of frequency 256, the number of beats heard are 1 per second. The frequency of tuning fork is [NCERT 1975, 81; MP PET 1985]
  A)
             257 done clear
  B)
             258 done clear
  C)
             256 done clear
  D)
             254 done clear
  View Solution play_arrow

• question_answer6)
  If two tuning forks A and B are sounded together, they produce 4 beats per second. A is then slightly loaded with wax, they produce 2 beats when sounded again. The frequency of A is 256. The frequency of B will be [CPMT 1976; RPET 1998]
  A)
             250 done clear
  B)
             252 done clear
  C)
             260 done clear
  D)
             262 done clear
  View Solution play_arrow

• question_answer7)
  The frequencies of two sound sources are 256 Hz and 260 Hz. At t = 0, the intensity of sound is maximum. Then the phase difference at the time t = 1/16 sec will be
  A)
             Zero                                          done clear
  B)
             p done clear
  C)
             p/2 done clear
  D)
             p/4 done clear
  View Solution play_arrow

• question_answer8)
  Two tuning forks have frequencies 450 Hz and 454 Hz respectively. On sounding these forks together, the time interval between successive maximum intensities will be [MP PET 1989; MP PMT 2003]
  A)
             1/4 sec                                     done clear
  B)
             1/2 sec done clear
  C)
             1 sec                                         done clear
  D)
             2 sec done clear
  View Solution play_arrow

• question_answer9)
  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 [MP PET 1989]
  A)
             334 done clear
  B)
             339 done clear
  C)
             343 done clear
  D)
             347 done clear
  View Solution play_arrow

• question_answer10)
  Two tuning forks of frequencies 256 and 258 vibrations/sec are sounded together, then time interval between consecutive maxima heard by the observer is [MP PET/PMT 1988]
  A)
             2 sec                                         done clear
  B)
             0.5 sec done clear
  C)
             250 sec                                     done clear
  D)
             252 sec done clear
  View Solution play_arrow

• question_answer11)
  A tuning fork gives 5 beats with another tuning fork of frequency 100 Hz. When the first tuning fork is loaded with wax, then the number of beats remains unchanged, then what will be the frequency of the first tuning fork [MP PMT 1985]
  A)
             95 Hz                                        done clear
  B)
             100 Hz done clear
  C)
             105 Hz                                      done clear
  D)
             110 Hz done clear
  View Solution play_arrow

• question_answer12)
  Tuning fork \[{{F}_{1}}\] has a frequency of 256 Hz and it is observed to produce 6 beats/second with another tuning fork \[{{F}_{2}}\]. When \[{{F}_{2}}\] is loaded with wax, it still produces 6 beats/second with \[{{F}_{1}}\]. The frequency of \[{{F}_{2}}\] before loading was [MP PET 1990]
  A)
             253 Hz                                      done clear
  B)
             262 Hz done clear
  C)
             250 Hz                                      done clear
  D)
             259 Hz done clear
  View Solution play_arrow

• question_answer13)
  A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is                                  [MP PMT 1990]
  A)
             156 Hz                                      done clear
  B)
             152 Hz done clear
  C)
             148 Hz                                      done clear
  D)
             160 Hz done clear
  View Solution play_arrow

• question_answer14)
  Two tuning forks A and B vibrating simultaneously produce 5 beats. Frequency of B is 512. It is seen that if one arm of A is filed, then the number of beats increases. Frequency of A will be                                     [MP PMT 1991]
  A)
             502 done clear
  B)
             507 done clear
  C)
             517 done clear
  D)
             522 done clear
  View Solution play_arrow

• question_answer15)
  The beats are produced by two sound sources of same amplitude and of nearly equal frequencies. The maximum intensity of beats will be ...... that of one source [CPMT 1999]
  A)
             Same                                        done clear
  B)
             Double done clear
  C)
             Four times                             done clear
  D)
             Eight times done clear
  View Solution play_arrow

• question_answer16)
  Beats are produced by two waves given by \[{{y}_{1}}=a\sin 2000\,\pi t\] and \[{{y}_{2}}=a\sin 2008\,\pi t\]. The number of beats heard per second is                                                     [CPMT 1990; DCE 1999]
  A)
             Zero                                          done clear
  B)
             One done clear
  C)
             Four                                          done clear
  D)
             Eight done clear
  View Solution play_arrow

• question_answer17)
  A tuning fork whose frequency as given by manufacturer is 512 Hz is being tested with an accurate oscillator. It is found that the fork produces a beat of 2 Hz when oscillator reads 514 Hz but produces a beat of 6 Hz when oscillator reads 510 Hz. The actual frequency of fork is [MNR 1979; RPMT 1999]
  A)
             508 Hz                                      done clear
  B)
             512 Hz done clear
  C)
             516 Hz                                      done clear
  D)
             518 Hz done clear
  View Solution play_arrow

• question_answer18)
  A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in tension produces lesser beats per second than before                                                        [NCERT 1984]
  A)
             460 Hz                                      done clear
  B)
             470 Hz done clear
  C)
             480 Hz                                      done clear
  D)
             490 Hz done clear
  View Solution play_arrow

• question_answer19)
  When a tuning fork A of unknown frequency is sounded with another tuning fork B of frequency 256 Hz, then 3 beats per second are observed. After that A is loaded with wax and sounded, the again 3 beats per second are observed. The frequency of the tuning fork A is [MP PMT 1994]
  A)
             250 Hz                                      done clear
  B)
             253 Hz done clear
  C)
             259 Hz                                      done clear
  D)
             262 Hz done clear
  View Solution play_arrow

• question_answer20)
  A source of sound gives five beats per second when sounded with another source of frequency \[100\,{{s}^{-1}}\]. The second harmonic of the source together with a source of frequency \[205\,{{s}^{-1}}\] gives five beats per second. What is the frequency of the source                                                                       [CBSE PMT 1995]
  A)
             \[105\,{{s}^{-1}}\]               done clear
  B)
             \[205\,{{s}^{-1}}\] done clear
  C)
             \[95\,{{s}^{-1}}\]                 done clear
  D)
             \[100\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer21)
  When two sound waves are superimposed, beats are produced when they have [MP PET 1995; CBSE PMT 1992, 99; DCE 2000; DPMT 2000, 01]
  A)
             Different amplitudes and phases done clear
  B)
             Different velocities done clear
  C)
             Different phases done clear
  D)
             Different frequencies done clear
  View Solution play_arrow

• question_answer22)
  Two tuning forks A and B give 4 beats per second. The frequency of A is 256 Hz. On loading B slightly, we get 5 beats in 2 seconds. The frequency of B after loading is [Haryana CEE 1996]
  A)
             253.5 Hz                                  done clear
  B)
             258.5 Hz done clear
  C)
             260 Hz                                      done clear
  D)
             252 Hz done clear
  View Solution play_arrow

• question_answer23)
  A tuning fork A of frequency 200 Hz is sounded with fork B, the number of beats per second is 5. By putting some wax on A, the number of beats increases to 8. The frequency of fork B is                                       [MP PMT 1996]
  A)
             200 Hz                                      done clear
  B)
             195 Hz done clear
  C)
             192 Hz                                      done clear
  D)
             205 Hz done clear
  View Solution play_arrow

• question_answer24)
  Two tuning forks, A and B, give 4 beats per second when sounded together. The frequency of A is 320 Hz. When some wax is added to B and it is sounded with A, 4 beats per second are again heard. The frequency of B is [MP PMT 1997]
  A)
             312 Hz                                      done clear
  B)
             316 Hz done clear
  C)
             324 Hz                                      done clear
  D)
             328 Hz done clear
  View Solution play_arrow

• question_answer25)
  Two tuning forks have frequencies 380 and 384 Hz respectively. When they are sounded together, they produce 4 beats. After hearing the maximum sound, how long will it take to hear the minimum sound        [MP PMT/PET 1998]
  A)
             \[\frac{1}{2}\]sec                done clear
  B)
             \[\frac{1}{4}\]sec done clear
  C)
             \[\frac{1}{8}\]sec                done clear
  D)
             \[\frac{1}{16}\]sec done clear
  View Solution play_arrow

• question_answer26)
  Beats are produced with the help of two sound waves of amplitudes 3 and 5 units. The ratio of maximum to minimum intensity in the beats is                       [MP PMT 1999]
  A)
             2 : 1                                           done clear
  B)
             5 : 3 done clear
  C)
             4 : 1                                           done clear
  D)
             16 : 1 done clear
  View Solution play_arrow

• question_answer27)
  Two waves of lengths 50 cm and 51 cm produced 12 beats per second. The velocity of sound is [CBSE PMT 1999; Pb. PET 2001; AFMC 2003]
  A)
             306 m/s                                   done clear
  B)
             331 m/s done clear
  C)
             340 m/s                                   done clear
  D)
             360 m/s done clear
  View Solution play_arrow

• question_answer28)
  Two waves \[y=0.25\sin 316\,t\] and \[y=0.25\sin 310\,t\] are travelling in same direction. The number of beats produced per second will be [CPMT 1993; JIPMER 2000]
  A)
             6     done clear
  B)
             3 done clear
  C)
             3/p done clear
  D)
             3p done clear
  View Solution play_arrow

• question_answer29)
  The couple of tuning forks produces 2 beats in the time interval of 0.4 seconds. So the beat frequency is  [CPMT 1996]
  A)
             8 Hz                                           done clear
  B)
             5 Hz done clear
  C)
             2 Hz                                           done clear
  D)
             10 Hz done clear
  View Solution play_arrow

• question_answer30)
  An unknown frequency x produces 8 beats per seconds with a frequency of 250 Hz and 12 beats with 270 Hz source, then x is                                             [CPMT 1997; KCET  2000]
  A)
             258 Hz                                      done clear
  B)
             242 Hz done clear
  C)
             262 Hz                                      done clear
  D)
             282 Hz done clear
  View Solution play_arrow

• question_answer31)
  Beats are produced by two waves                    \[{{y}_{1}}=a\sin 1000\,\pi t,\] \[{{y}_{2}}=a\sin 998\pi t\]            The number of beats heard/sec is                                                [KCET 1998]
  A)
             0     done clear
  B)
             2 done clear
  C)
             1     done clear
  D)
             4 done clear
  View Solution play_arrow

• question_answer32)
  The wavelengths of two waves are 50 and 51 cm respectively. If the temperature of the room is 20oC, then what will be the number of beats produced per second by these waves, when the speed of sound at 0oC is 332 m/sec [UPSEAT 1999]
  A)
             14   done clear
  B)
             10 done clear
  C)
             24   done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer33)
  Maximum number of beats frequency heard by a human being is                                            [RPMT 2000]
  A)
             10   done clear
  B)
             4 done clear
  C)
             20   done clear
  D)
             6 done clear
  View Solution play_arrow

• question_answer34)
  Two sound waves of slightly different frequencies propagating in the same direction produce beats due to                                                                                            [MP PET 2000]
  A)
             Interference                         done clear
  B)
             Diffraction done clear
  C)
             Polarization                           done clear
  D)
             Refraction done clear
  View Solution play_arrow

• question_answer35)
  On sounding tuning fork A with another tuning fork B of frequency 384 Hz, 6 beats are produced per second. After loading the prongs of A with some wax and then sounding it again with B, 4 beats are produced per second. What is the frequency of the tuning fork A [MP PMT 2000]
  A)
             388 Hz                                      done clear
  B)
             380 Hz done clear
  C)
             378 Hz                                      done clear
  D)
             390 Hz done clear
  View Solution play_arrow

• question_answer36)
  It is possible to hear beats from the two vibrating sources of frequency                                                 [UPSEAT 2001]
  A)
             100 Hz and 150 Hz               done clear
  B)
             20 Hz and 25 Hz done clear
  C)
             400 Hz and 500 Hz               done clear
  D)
             1000 Hz and 1500 Hz done clear
  View Solution play_arrow

• question_answer37)
  A tuning fork gives 4 beats with 50 cm length of a sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is                                    [MP PMT 2001]
  A)
             396 done clear
  B)
             400 done clear
  C)
             404 done clear
  D)
             384 done clear
  View Solution play_arrow

• question_answer38)
  Two sound waves of wavelengths 5m and 6m formed 30 beats in 3 seconds. The velocity of sound is                                                                                           [EAMCET 2001]
  A)
             300 ms?1                                  done clear
  B)
             310 ms?1 done clear
  C)
             320 ms?1                                  done clear
  D)
             330 ms?1 done clear
  View Solution play_arrow

• question_answer39)
  The wavelength of a particle is 99 cm and that of other is 100 cm. Speed of sound is 396 m/s. The number of beats heard is                                                      [DCE 2001]
  A)
             4     done clear
  B)
             5 done clear
  C)
             1     done clear
  D)
             8 done clear
  View Solution play_arrow

• question_answer40)
  A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The frequency of the unknown fork is  [KCET 1998; AIEEE 2002]
  A)
             286 cps                                    done clear
  B)
             292 cps done clear
  C)
             294 cps                                    done clear
  D)
             288 cps done clear
  View Solution play_arrow

• question_answer41)
  A tuning fork vibrates with 2 beats in 0.04 second. The frequency of the fork is [AFMC 2003]
  A)
             50 Hz                                        done clear
  B)
             100 Hz done clear
  C)
             80 Hz                                        done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer42)
  Two sound sources when sounded simultaneously produce four beats in 0.25 second. the difference in their frequencies must be                                                   [BCECE 2003]
  A)
             4     done clear
  B)
             8 done clear
  C)
             16   done clear
  D)
             1 done clear
  View Solution play_arrow

• question_answer43)
  A tuning fork of known frequency 256 Hz makes 5 beats per second with the vibrating string of a piano. The beat frequency decreases to 2 beats per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was  [AIEEE 2003]
  A)
             256 + 5 Hz                               done clear
  B)
             256 + 2Hz done clear
  C)
             256 ? 2 Hz                               done clear
  D)
             256 ? 5Hz done clear
  View Solution play_arrow

• question_answer44)
  When temperature increases, the frequency of a tuning fork     [AIEEE 2002]
  A)
             Increases                                done clear
  B)
             Decreases done clear
  C)
             Remains same                      done clear
  D)
             Increases or decreases depending on the material done clear
  View Solution play_arrow

• question_answer45)
  Two strings X and Y of a sitar produce a beat frequency 4 Hz. When the tension of the string Y is slightly increased the beat frequency is found to be 2 Hz. If the frequency of X is 300 Hz, then the original frequency of Y was  [UPSEAT 2000]
  A)
             296 Hz                                      done clear
  B)
             298 Hz done clear
  C)
             302 Hz                                      done clear
  D)
             304 Hz done clear
  View Solution play_arrow

• question_answer46)
  The frequency of tuning forks A and B are respectively 3% more and 2% less than the frequency of tuning fork C. When A and B are simultaneously excited, 5 beats per second are produced. Then the frequency of the tuning fork 'A' (in Hz) is                                                                   [EAMCET 2001]
  A)
             98   done clear
  B)
             100 done clear
  C)
             103 done clear
  D)
             105  done clear
  View Solution play_arrow

• question_answer47)
  When a tuning fork vibrates, the waves produced in the fork are                                                              [AFMC 2001]
  A)
             Longitudinal                          done clear
  B)
             Transverse done clear
  C)
             Progressive                           done clear
  D)
             Stationary done clear
  View Solution play_arrow

• question_answer48)
  Two vibrating tuning forks produce progressive waves given by \[{{Y}_{1}}=4\sin 500\pi t\]and \[{{Y}_{2}}=2\sin 506\pi t.\] Number of beats produced per minute is                                                     [CBSE PMT 2005]
  A)
             360 done clear
  B)
             180 done clear
  C)
             3     done clear
  D)
             60 done clear
  View Solution play_arrow

• question_answer49)
  When a tuning fork produces sound waves in air, which one of the following is same in the material of tuning fork as well as in air                                                                     [AFMC 2005]
  A)
             Wavelength                          done clear
  B)
             Frequency done clear
  C)
             Velocity                                   done clear
  D)
             Amplitude done clear
  View Solution play_arrow

• question_answer50)
  The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency                                             [KCET 2005]
  A)
             10 Hz                                        done clear
  B)
             360 Hz done clear
  C)
             216 Hz                                      done clear
  D)
             6 Hz done clear
  View Solution play_arrow

• question_answer51)
  A sound source of frequency 170 Hz is placed near a wall. A man walking from a source towards the wall finds that there is a periodic rise and fall of sound intensity. If the speed of sound in air is 340 m/s the distance (in metres) separating the two adjacent positions of minimum intensity is [MNR 1992; UPSEAT 2000; CPMT 2002]
  A)
             1/2                                            done clear
  B)
             1 done clear
  C)
             3/2 done clear
  D)
             2 done clear
  View Solution play_arrow