EASY
JEE Main
IMPORTANT
Earn 100

Find the angular separation between the consecutive bright fringes in a Young's double slit experiment with blue-green light of wavelength 500 nm. The separation between the slits is 2.0×10-3 m.

Important Questions on Light Waves

MEDIUM
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 10
A source emitting light of wavelengths 480 nm and 600 nm is used in a double slit interference experiment. The separation between the slits is 0.25 mm and the interference is observed on a screen placed at 150 cm from the slits. Find the linear separation between the first maximum (next to the central maximum) corresponding to the two wavelengths.
EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 11
A white light is used in a Young's double-slit experiment. Find the minimum order of the violet fringe (λ=400 nm) which overlaps with a red fringe (λ=700 nm).
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 15
In Young's double-slit experiment using monochromatic light, the fringe pattern shifts by a certain distance on the screen when a mica sheet of refractive index 1·6 and thickness 1·964 micron (1 micron=10-6 m) is introduced in the path of one of the interfering waves. The mica sheet is then removed and the distance between the screen and the slits is doubled. It is found that the distance between the successive maxima now is the same as the observed fringe-shift upon the introduction of the mica sheet. Calculate the wavelength of the monochromatic light used in the experiment.
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 16
A mica strip and a polystyrene strip are fitted on the two slits of a double-slit apparatus. The thickness of the strips are 0.50 mm and the separation between the slits is 0.12 cm. The refractive index of mica and polystyrene are 1.58 and 1.55, respectively for the light of a wavelength 590 nm which is used in the experiment. The interference is observed on a screen a distance one meter away.
(a) The fringe-width in n.9×10-4 m, then find the value of n.
EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 17
Two transparent slabs having equal thickness but different refractive indices μ1 and μ2 are pasted side by side to form a composite slab. This slab is placed just after the double slit in a Young's experiment so that the light from one slit goes through one material and the light from the other slit goes through the other material. The minimum thickness of the slab so that there is a minimum at the point P0 which is equidistant from the slits is λxμ1-μ2. Find x.
MEDIUM
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 18

A thin paper of thickness 0.02 mm having a refractive index 1.45 is placed across one of the slits in Young's double-slit experiment. The paper transmits 49th of the light energy falling on it.

(a) Find the ratio of the maximum intensity to the minimum intensity in the fringe pattern.

(b) How many fringes will cross through the centre if an identical paper piece is placed on the other slit also? The wavelength of the light used is 600 nm.

HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 19
A Young's double slit apparatus has slits separated by 0.28 mm and a screen 48 cm away from the slits. The whole apparatus is immersed in water and the slits are illuminated by the red light (λ=700 nm in vacuum). Find the fringe-width of the pattern formed on the screen.
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 17 - Light Waves>EXERCISES>Q 20
A parallel beam of monochromatic light is used in a Young's double slit experiment. The slits are separated by a distance d and the screen is placed parallel to the plane of the slits. Show that if the incident beam makes an angle θ=sin-1λ2d with the normal to the plane of the slits, there will be a dark fringe at the centre P0 of the pattern.