Dispersion by Prism vs. Slab – Rankers Physics

Refraction by Prism: Practice Problem & Solution

Assertion (A): When light passes through a prism, it disperses while if the same light passes through a rectangular glass slab of same material, it doesn't disperse. Reason (R): Dispersive power of prism is non zero while that of glass slab is zero.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Refraction by Prism. Understanding the underlying formula is key to arriving at the correct answer below:

A prism disperses light because its non-parallel surfaces separate colors due to varying refractive indices. A rectangular slab also disperses light internally, but the emergent rays are parallel, resulting in no net angular dispersion. Dispersive power is a material property and is non-zero for any dispersive medium, including glass slabs.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. A lens having focal length f and aperture of diameter d forms an image of intensity I. Aperture of diameter d/2 in central region of lens is covered by a black paper. Focal length of lens and intensity of image now will be respectively: (2010 Pre)
2. The angle of a prism is ‘A’. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence 2A on the first surface returns back through the same path after suffering reflection at the silvered surface. The refractive index μ, of the prism is :
3. A convex mirror of focal length \(10\text{ cm}\) forms an image which is \(\frac{1}{3}\) times of the height of a real object. The distance of the object from the mirror is
4. The refractive index of water is 1.33. What will be the speed of light in water? (1996)
5. Assertion (A): When a monochromatic beam of light is incident from one medium to another, the frequency of incident, reflected and refracted rays are equal. Reason (R): The incident, reflected and refracted rays are co-planar.