Describe the nature of image formed when the object is placed at a distance of 20cm from a concave mirror of focal length 10cm.

A convex lens is immersed in a liquid of refractive index greater than that of glass. How will the nature of lens change?

A vertical ray of light strikes the horizontal surface of some water:

1. What is the angle of incidence?
2. What is the angle of refraction?

The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should the position of the object be relative to the mirror? Draw ray diagram to justify your answer.

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12cm and its sharp image is formed at a distance of 24cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

An object is placed at a distance of 30 cm from a concave lens of focal length 15 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.

Why does a ray of light passing through the centre of curvature of a concave mirror gets reflected along same path after reflection?

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

A convex mirror used as a rear-view mirror in a car has a radius of curvature of 3m. If a bus is located at a distance of 5m from this mirror, find the position of image. What is the nature of the image?