Question

A convex lens of focal length 6 cm is held 4 cm from a newspaper which has print 0.5 cm high. By calculation, determine the size and nature of the image produced.

Answer 1

Answer:

The size of the image produced is 1.5 cm

Explanation:

According to the problem the size of the object is 0.5 cm

the object distance, d = 4 cm

focal length of the lens , l= 6 cm

Now let  the image distance be u .

Therefore, from the lens makers formula

1/v−1/u=1/l

⇒1/v=1/u−1/f

      =1/4−1/6

⇒1/v=3−2/12

      =1/12

⇒v=12 cm

Now ,magnification  m=v/u

                                   =12/4=3

Again , magnification =image size/object size

                             ⇒image size=m×object size=3×0⋅5=1.5 cm