Question

Assertion: the focal length of convex mirror will increase if the mirror placed in water
Reason: the focal length of a convex mirror of radius = ,f= r/2
1.both A and R are true but R is the correct explanation of A
2.both A and R are true but R is the not correct explanation of A
3 .A is true but R is false
4. both A and R are false​

Answer 1

Answer:

Assertion is false and Reason is true

Explanation:

Focal length is the property of mirror and is independent of the medium in which it is placed

Answer 2

4. both A and R are false​.

• Because the focal length of the spherical mirror does not depend on the medium in which it is placed.
• The focal length of a convex mirror of radius R  is equal to. $f=\frac{r}{2}$  and the focal length is independent of the material in which it is placed.
• It depends on the refractive index of the glass from which it is made, and on the curvature of its two surfaces.

So, both the assertion and reason are false.