Paragraph: The figure shows a surface X Y separating two...

Paragraph: The figure shows a surface

X Y

separating two transparent media, medium-1 and medium-2. The lines

a b

and

c d

represent wavefronts of a light wave travelling in medium-1 and incident on

X Y

. The lines ef and

g h

represent wavefronts of the light wave in medium-2 after refraction. Paragraph: The figure shows a surface X Y separating two transparent media, medium-1 and medium-2. The lines a b and c

Paragraph: The figure shows a surface X Y separating two transparent media, medium-1 and medium-2. The lines a b and c

Question: The phases of the light wave at

c, d, e

and

f

are

\phi_c, \phi_d, \phi_e

and

\phi_f

, respectively. It is given that

\phi_c \neq \phi_f

Options

A $\phi_c$ cannot be equal to $\phi_d$
B $\phi_d$ can be equal to $\phi_e$
C $\left(\phi_d-\phi_f\right)$ is equal to $\left(\phi_c-\phi_e\right)$
D $\left(\phi_d-\phi_c\right)$ is not equal to $\left(\phi_f-\phi_e\right)$

Correct answer

C. $\left(\phi_d-\phi_f\right)$ is equal to $\left(\phi_c-\phi_e\right)$

Step-by-step solution

All points on a wavefront are at the same phase.

\begin{array}{rlrl} \therefore & \phi_d & =\phi_c \text{ and } \phi_f=\phi_e \\ & \therefore & \phi_d-\phi_f & =\phi_c-\phi_e \end{array}

Hence, the correct option is (c).

Practice Ray Optics on Quantrex Academy →

More from Ray Optics

A double convex lens made of glass of refractive index 1.5 and radii of curvature of the… JEE Advanced 2026 A beam of polychromatic light passes through a thin prism of prism angle 6^∘ . The… JEE Advanced 2026 Consider two isosceles prisms 1 and 2 with prism angles A_1 and A_2 and refractive… JEE Advanced 2026 A thin biconvex lens is prepared from the glass ( μ=1.5 ) both curved surfaces of which… JEE Main 2026 Light ray incident along a vector AO ( AO = 2 i -3 j ) emerges out along vector OB ( OB =… JEE Main 2026 Angle of minimum deviation is equal to the half of the angle of prism in an equilateral… JEE Main 2026 A concave mirror of focal length 10 cm forms an image which is double the size of object… JEE Main 2026 A spherical interface lens of radius R separates two media of refractive indices 1 and… JEE Main 2026 Full Ray Optics list All JEE Advanced PYQs