Focal Length and Wavelength – Rankers Physics

Reflection by Spherical Mirrors: Practice Problem & Solution

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

Short Solution (Best for NEET):

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

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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