1
JEE Main 2025 (Online) 2nd April Morning Shift
MCQ (Single Correct Answer)
+4
-1
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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 :

A
$\cos ^{-1}(2 / 3)$
B
$\cos ^{-1}\left(\frac{1}{\sqrt{3}}\right)$
C
$\cos ^{-1}\left(\frac{1}{3}\right)$
D
$\cos ^{-1}\left(\sqrt{\frac{2}{3}}\right)$
2
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
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At the interface between two materials having refractive indices $n_1$ and $n_2$, the critical angle for reflection of an em wave is $\theta_{1C}$. The $\mathrm{n}_2$ material is replaced by another material having refractive index $n_3$ such that the critical angle at the interface between $n_1$ and $n_3$ materials is $\theta_{2 C}$. If $n_3>n_2>n_1 ; \frac{n_2}{n_3}=\frac{2}{5}$ and $\sin \theta_{2 C}-\sin \theta_{1 C}=\frac{1}{2}$, then $\theta_{1 C}$ is :
A

$ \sin^{-1}\left( \frac{1}{6n_1} \right) $

B

$ \sin^{-1}\left( \frac{1}{3n_1} \right) $

C

$ \sin^{-1}\left( \frac{5}{6n_1} \right) $

D

$ \sin^{-1}\left( \frac{2}{3n_1} \right) $

3
JEE Main 2025 (Online) 24th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
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In a Young's double slit experiment, three polarizers are kept as shown in the figure. The transmission axes of $P_1$ and $P_2$ are orthogonal to each other. The polarizer $P_3$ covers both the slits with its transmission axis at $45^{\circ}$ to those of $P_1$ and $P_2$. An unpolarized light of wavelength $\lambda$ and intensity $I_0$ is incident on $P_1$ and $P_2$. The intensity at a point after $P_3$ where the path difference between the light waves from $s_1$ and $s_2$ is $\frac{\lambda}{3}$, is

JEE Main 2025 (Online) 24th January Evening Shift Physics - Wave Optics Question 13 English

A
$\mathrm{I}_0$
B
$\frac{\mathrm{I}_0}{3}$
C
$\frac{\mathrm{I}_0}{4}$
D
$\mathrm{\frac{I_0}{2}}$
4
JEE Main 2025 (Online) 24th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Young's double slit inteference apparatus is immersed in a liquid of refractive index 1.44. It has slit separation of 1.5 mm . The slits are illuminated by a parallel beam of light whose wavelength in air is 690 nm . The fringe-width on a screen placed behind the plane of slits at a distance of 0.72 m , will be:

A
0.63 mm
B
0.33 mm
C
0.46 mm
D
0.23 mm
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