Question

Q1A concave mirror and a convex lens are held separately in water. What changes (if any)
do you expect in the focal length of either?
Q2Distinguish between a real and virtual image.
Q3Distinguish between a convex and concave mirror.

Answer 1

Answer:

Q2) real image :-

The image formed when rays of light meet at a point after reflection/refraction is called real image

virtual image:-

The image formed when rays of light appear to meet (when diverging rays are extended) at a point is called a virtual image.

Q3) concave mirror:-a concave mirror has the reflecting surface that caves inwards. concave mirrors they are used to focus light .the image formed by a concave mirror varies size depending on the position of the object with respect to the mirror.the image can e real or virtual,erect or inverted and magnified, diminished or of the same size as that of the object , all depending on the position of the object

the are also called converging mirrors

convex mirror:-

convex mirror is a curved mirror for which the reflective surface bulges out towards the light source. convex mirrors reflect outwards (diverging light rays) and therefore they are not used to focus light. the image is virtual, erect and smaller in size than the object ,but gets larger (maximum upto the size of the object ) as the object comes towards the mirror. such mirrors are called diverging mirrors

sorry I don't know the answer for Q1