JEE Main · 2024 · 29 Jan 2024 · Shift 2 · Wave Optics

WhatsApp Email

In Young's double slit experiment, light from two identical sources are superimposing on a screen. The path difference between the two lights reaching at a point on the screen is

\frac{7 λ}{4}

. The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is :

(A) $1/2$ ✓ Correct
(B) $3/4$
(C) $1/3$
(D) $1/4$

Answer: (A)

Solution

At a point with path difference

Δ x

, the resultant intensity from two equal sources is

I = I_{ma x} cos^{2} (\frac{ϕ}{2}), ϕ = \frac{2 π}{λ} Δ x

With

Δ x = \frac{7 λ}{4}

ϕ = \frac{2 π}{λ} \times \frac{7 λ}{4} = \frac{7 π}{2}

\frac{I}{I _{ma x}} = cos^{2} (\frac{7 π}{4}) = cos^{2} (2 π - \frac{π}{4}) = cos^{2} (\frac{π}{4}) = \frac{1}{2}

JEE Main · 2024 · 29 Jan 2024 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Wave Optics →

More JEE Main questions on Wave Optics

Given below are two statements:
Statement I: In a Young's double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits
Statement II : In a Young's double slit experiment, the angular separation of fringes will inc …
JEE Main 2026View solution →
In a Young's double slit experiment set up, the two slits are kept 0.4 mm apart and screen is placed at 1 m from slits. If a thin transparent sheet of thickness $20 μ m$ is introduced in front of one of the slits then centre bring fringe shifts by 20 mm on the screen …
JEE Main 2026View solution →
In two separate Young's double-slit experimental set-ups, two monochromatic light sources of different wavelengths are used to get fringes of equal width. The ratios of the slit separations and that of the wavelengths of light used are $2 : 1$ and $1 : 2$ respectively. The correspo …
JEE Main 2026View solution →
When an unpolarized light falls at a particular angle on a glass plate (placed in air), it is observed that the reflected beam is linearly polarized. The angle of refracted beam with respect to the normal is $____$ .
( $tan^{- 1} (1.52) = 57. 7^{\circ}$ , refractive indices of air a …
JEE Main 2026View solution →
Given below are two statements:

Statement-I: A plane wave after passing through prism remains as plane wave but passing through small pin hole may become spherical wave.
Statement-II: The curvature of a spherical wave emerging from a slit will increase for increasing slit width. …
JEE Main 2026View solution →
In the Young's double slit experiment the intensity produced by each one of the individual slits is $I_{0}$ . The distance between two slits is 2 mm. The distance of screen from slits is 10 m. The wavelength of light is $6000 \overset{˚}{A}$ . The intensity of light on the screen in front of …
JEE Main 2026View solution →