A ray of light passes through four transparent media with refractive index μ1, μ2, μ3, and μ4 as shown in the figure. The surfaces of all media are parallel. If BC and DE are parallel, we must have:
μ2 = μ4
For the emergent ray to be parallel to the incident ray, the conditions for refraction must ensure that the final deviation cancels out any intermediate deviations.
From Snell’s Law, if the ray passes through multiple layers and the emergent ray is parallel to the original, the refractive indices must satisfy μ2 = μ4.
Thus, the correct answer is (c) μ2 = μ4.
A Convex mirror produces the magnification 1/3 and 1/4 when the object is placed at the points P and Q in front of the mirror.
Which of the following statements are correct?
Choose the correct answer from the options given below:
For insulators and semiconductors, the resistance decreases with an increase in temperature because:

Light of uniform intensity shines perpendicularly on a totally absorbing surface, fully illuminating the surface. If the area of the surface is decreased, what is the effect on radiation pressure?
A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal to the angle of emergence, and each of these angles is equal to (3/4)th of the angle of the prism. The angle of deviation is: