At what distance should an object be placed from a convex lens of focal length 18 cm to obtain an image at 36 cm from it? What will be the magnification produced in this case?

When an object is placed at a distance of 60 cm from a convex mirror the magnification produced is 1/2. Where should the object be placed to get a magnification of 1/3.

A concave lens has focal length of 20cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at a distance of 15 cm from the lens? Also calculate the size of the image formed.

You have two lenses A and B of focal lengths + 10 cm and – 10 cm respectively. State the nature and power of each lens. Which of the two lenses will form a virtual and magnified image of an object placed 8 cm from the lens? Draw a ray diagram to justify your answer.

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

(i) In front of a convex lens at F,

(ii) At 3F of a convex lens,

(iii) Between the lens and infinity of a concave lens.