Question

A  pencil  is placed 5 cm is placed 30 cm from a convex lens produced an image on a screen placed 60 cm away from the lens.  Identify the types of lens and calculate its focal length?​

Answer 1

Answer:

1/f =1/v-1/u

1/f=1/60-(1/-30)

1/f =1/60+1/30

1/f=1/60 + 2/60

1/f =3/60

1/f = 1/30

f=30 m