a) Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
i) 0.50 m
ii) 0.25 m
0.15 m
b) Which of the above cases represents the use of convex lens in a film projector, in a camera, and as a magnifying glass?

Explanation

a) i) `v=+0.33 m`, The image is formed 0.33 m behind the lens, m`=-0.66`, Real and inverted ii) `v=+1.00m`, The image is formed 1.00 m behind the lens, `m=-4.0`, Virtual and erect b) Film projector, Case ii), Camera, Case (i), Magnifying glass, case(iii)