Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Wave Optics question

2003 · Shift 0 · Q139
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Wave Optics
  5. /2003 · Shift 0 · Q139

Wave Optics question

2003 · Shift 0 · Q139

JEE MainPhysicsWave OpticsMCQ+4 / −1
To demonstrate the phenomenon of interference, we require two sources which emit radiation
  1. A
    of nearly the same frequency
  2. B
    of the same frequency
  3. C
    of different wavelengths
  4. D
    of the same frequency and having a definite phase relationship
View written solutionFree

Correct answer: D

  1. Condition for sustained interference

To observe a clear and stable interference pattern, the two sources must be coherent.

Two coherent sources must satisfy:

  • They emit waves of the same frequency (equivalently, same wavelength in the same medium), and
  • They maintain a constant phase difference (definite phase relationship).
  1. Check each option

  • A: of nearly the same frequency
    If the frequencies are only nearly equal, the phase difference keeps changing with time, so the interference pattern will not remain steady. This is not sufficient for sustained interference.

  • B: of the same frequency
    Same frequency alone is not enough. If the phase relationship is random, no stable interference pattern is obtained.

  • C: of different wavelengths
    Different wavelengths mean different frequencies (in the same medium), so coherent sustained interference is not obtained.

  • D: of the same frequency and having a definite phase relationship
    This is exactly the condition for coherence, hence this is correct.

  1. Conclusion

For interference, the two sources must emit radiation of the same frequency and with a definite phase relationship.

Therefore, the correct option is: D\boxed{\text{D}}D​

  1. Comparison with stored answer

Stored correct answer is D, which matches the derived answer.

Previous

More from Wave Optics

  • A light wave is propagating with plane wave fronts of the type x+y+z= constant. Th angle made by the direction of wave propagation with the x-axis is :2025 · MCQ
  • If the measured angular separation between the second minimum to the left of the central maximum and the third minimum to the right of the central maximum is 30∘ in a single slit diffraction pattern recorded using 628 nm light,…2025 · Numerical
  • Two coherent monochromatic light beams of intensities 4I and 9I are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is xI. The value of x is ​…2025 · Numerical
  • Two monochromatic light beams have intensities in the ratio 1:9. An interference pattern is obtained by these beams. The ratio of the intensities of maximum to minimum is2025 · MCQ
  • Width of one of the two slits in a Young's double slit interference experiment is half of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is :2025 · MCQ
  • A monochromatic light of frequency 5×1014 Hz travelling through air, is incident on a medium of refractive index ' 2 '. Wavelength of the refracted light will be :2025 · MCQ
  • In a Young's double slit experiment, the slits are separated by 0.2 mm . If the slits separation is increased to 0.4 mm , the percentage change of the fringe width is :2025 · MCQ
  • Two polarisers P1​ and P2​ are placed in such a way that the intensity of the transmitted light will be zero. A third polariser P3​ is inserted in between P1​ and P2​, at particular angle between P2​ and P3​. The transmitted…2025 · MCQ