1. If one of two identical slits producing interference in Young’… - Vidyadip

Question

If one of two identical slits producing interference in Young’s experiment is covered with glass, so that the light intensity passing through it is reduced to 50%, find the ratio of the maximum and minimum intensity of the fringe in the interference pattern.
What kind of fringes do you expect to observe if white light is used instead of monochromatic light?

✓

Answer

$\text{I}_1=\frac{\text{I}}{2}$

$\text{I}_2=\text{I}$
$\frac{\text{I}_{\text{max}}}{\text{I}_{\text{min}}}=\bigg(\frac{\sqrt{\text{I}_1}+\sqrt{\text{I}_2}}{\sqrt{\text{I}_1}-\sqrt{\text{I}_2}}\bigg)^2$
$=\Bigg(\frac{\sqrt{\frac{\text{I}}{2}}+\sqrt{\text{I}}}{\sqrt{\frac{\text{I}}{2}}-\sqrt{\text{I}}}\Bigg)^2$
$=\bigg(\frac{1+\sqrt{2}}{1-\sqrt{2}}\bigg)^2$
$=\frac{2+1+2\sqrt{2}}{2+1-2\sqrt{2}}$
$=\frac{3+2\sqrt{2}}{3-2\sqrt{2}}$

If we use white light, central fringe will be white, then there will be colourful fringes on both sides, starting from violet to red (fringe width $\propto$ wavelength) and then there will be general illumination of screen.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Wave Optics→Wave Optics — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

Calculate the number of photons emitted per second by a 10W sodium vapour lamp. Assume that 60% of the consumed energy is converted into light. Wavelength of sodium light = 590nm.

A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet.

In which direction will it move?
What will be the direction of it’s magnetic moment?

The following table shows some measurements of the decay rate of a radionuclide sample. Find the disintegration constant.

Time (min)	lnR (Bq)
36	5.08
100	3.29
164	1.54
218	0

Consider the situation shown in figure Show that if the blocks are displaced slightly in opposite directions and released, they will execute simple harmonic motion. Calculate the time period.

Is it easier to take out a nucleon from carbon or from iron? Fi-om iron or from lead?

An electric bulb, connected to a make and break power supply, switches off and on every second in its rest frame. What is the frequency of its switching off and on as seen from a spaceship travelling at a speed 0.8c?

Red light, however bright it is, cannot produce the emission of electrons from a clean zinc surface. But even weak ultraviolet radiation can do so. Why?
Electrons are emitted from the cathode of negligible work function, when photons of wavelength $\lambda$ are incident on it. Derive the expression for the de Broglie wavelength of the electrons emitted in terms of the wavelength of the incident light.

A parallel$-$plate capacitor having plate area $25\ cm^2$ and separation $1.00\ mm$ is connected to a battery of $6.0V.$ Calculate the charge flown through the battery. How much work has been done by the battery during the process?

The time taken by Mars to revolve round the sun is 1.88 years. Find the ratio of average distance between Mars and the sun to that between the earth and the sun.

Figure. shows a vessel partitioned by a fixed diathernnc separator. Different ideal gases are filled in the two parts. The rms speed of the molecules in the left part equals the mean speed of the molecules in the right part. Calculate the ratio of the mass of a molecule in the left part to the mass of a molecule in the right part.