Assertion: The radius of curvature of a mirror is double of the focal length. Reason: A concave mirror of focal length f in air is used in a medium of refractive index 2. Then the focal length of mirror in medium becomes 2f.

Question

Assertion: The radius of curvature of a mirror is double of the focal length. Reason: A concave mirror of focal length f in air is used in a medium of refractive index 2. Then the focal length of mirror in medium becomes 2f. (A) If both assertion and reason are true and reason is the correct explanation of assertion (B) If both assertion and reason are true but reason is not the correct explanation of assertion (C) If assertion is true but reason is false (D) If both assertion and reason are false

Tardigrade Admin · Accepted Answer

Focal length of a mirror does not depend on the medium in which mirror is held. It depends on the radius of the sphere from which it is made. However focal length of a lens does depend on medium.

Q. Assertion : The radius of curvature of a mirror is double of the focal length. Reason: A concave mirror of focal length f in air is used in a medium of refractive index 2. Then the focal length of mirror in medium becomes 2f.

If both assertion and reason are true and reason is the correct explanation of assertion

If both assertion and reason are true but reason is not the correct explanation of assertion

If assertion is true but reason is false

If both assertion and reason are false

Focal length of a mirror does not depend on the medium in which mirror is held. It depends on the radius of the sphere from which it is made. However focal length of a lens does depend on medium.

Q. Assertion : The radius of curvature of a mirror is double of the focal length.
Reason: A concave mirror of focal length $f$ in air is used in a medium of refractive index $2$ . Then the focal length of mirror in medium becomes $2 f$ .