The radius of curvature of a spherical mirror is 20 cm. What is its focal length? Therefore, the focal length of the spherical mirror is 10 cm.

From this formula we can say that focal length of lens is inversely proportional to refractive index of material of lens medium. i.e As Refractive index (m) increases focal length (f) of lens decreases.

The relation between focal length (f) and radius of curvature (R) of a spherical mirror is that the focal length is equal to half of the radius of curvature i.e. f=R2.

Answer. Hence, the focal length of the given convex mirror is 16 cm.

16 cm. So the focal length of the convex mirror is 16cm.

Answer. The focal length of the given convex mirror is 30cm.

Answer. seee…..the focal length of concave/convex mirror = half of its radius of curvature…..

Thus, focal length of convex mirror, f=16 cm.

Hence, the focal length of the concave mirror is 20cm.

Answer. no. we can’t calculate.

When kept inside water, the laws of reflections are still valid, thus the focal length of the concave mirror does not change. Since water has a greater value of refractive index than air, the converging power of the lens will be less as compared to air. Thus the focal length of the convex lens will increase.

Accepted Answer: The focal length of the concave mirror does not change when it is immersed in water because focal length of a mirror does not depend upon the refractive index of the medium. Therefore, when a convex lens is dipped into water, its focal length increases.