Question

we are given a convex lens of focal length 20cm draw a ray diagram to show the nature size and position of image formed when the object is kept at a distance of 15 and 35 cm

Answer 1

Given focal length of the lens is f= 20cm   so 2f =40cm.

Case 1- When that object is placed at the distance of 35cm from lens then that object is between  f and 2f.

So the image which is formed beyond the 2f and the type of image is enlarged and real inverted.

Case2 - When that object is kept at the distance of 15cm from lens then that object is kept between optical center and the f. so the type of image is enlarged and virtual erect.