NEET Physics Wave Optics : Multiple Choice Previous Years Questions MCQs 5

TL;DR

Young's double-slit experiment is analyzed with respect to the location and coincidence of interference fringes, as well as the ratio of intensities and the effect of closing one slit on the interference pattern.

Transcript

hello friends this video unmeet wave optics was brought to you by Ram sharam no more fear from exam question number 17 in Young's double-slit experiment the slits are 2 millimeter apart and are illuminated by photons of two wavelengths lambda 1 is equal to 12 thousand angstrom and lambda 2 is equal to 10,000 angstrom okay so fine at what minimum di... Read More

Key Insights

• 😑 The position of bright fringes in Young's double-slit experiment can be determined using the expression Yn = nλD/d.
• 🔅 The minimum distance from the central fringe is found by equating the positions of bright fringes for two different wavelengths and solving for the ratio of the bright fringe numbers.
• 😑 The ratio of maximum and minimum intensities in interference patterns caused by two coherent sources of different intensities can be calculated using a derived expression.

Questions & Answers

Q: How is the position of a bright fringe in Young's double-slit experiment determined?

The position of a bright fringe is determined by the expression Yn = nλD/d, where Yn is the position of the nth bright fringe, λ is the wavelength of light, D is the distance from the screen to the slit, and d is the distance between the two slits.

Q: In the video, what is the significance of finding the minimum distance where two bright fringes coincide?

The minimum distance from the central fringe represents the specific point where a bright fringe from one interference pattern coincides with a bright fringe from the other pattern, providing insight into the interference of light waves of different wavelengths.

Q: How is the ratio of intensities calculated in the interference pattern caused by two coherent sources of different intensities?

The ratio of maximum intensity to minimum intensity is equal to the square of the square root of the sum of the square roots of the intensities of the two sources, divided by the square root of the difference between the square roots of the intensities.

Q: What is the effect of closing one of the slits in Young's double-slit experiment?

When one slit is closed, the intensity of light coming out from that slit becomes zero, resulting in a decrease in the net intensity of the interference pattern at the central fringe.

Summary & Key Takeaways

• The video discusses Young's double-slit experiment, where two slits are illuminated by photons of different wavelengths, and the minimum distance from the central bright fringe where two bright fringes coincide is calculated.

• The video also explains the ratio of maximum and minimum intensities in interference patterns caused by two coherent sources of different intensities.

• Additionally, the video explores the intensity at the central fringe in the interference pattern when one of the slits is closed.