Focal Length and Wavelength – Rankers Physics
Topic: Ray Optics
Subtopic: Reflection by Spherical Mirrors

Focal Length and Wavelength

Assertion (A): The focal length of spherical mirror does not depend on the wavelength of light.
Reason (R): The number of wavelengths in the visible region of spectrum are infinite.
 
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:

Assertion (A) is true as focal length of spherical mirrors depends only on its radius of curvature, not refractive index or wavelength.


Reason (R) is false. The visible spectrum is a continuous range, not an infinite countable number of wavelengths.
So, (A) is true but (R) is false.

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