Question

A point object is placed on the principal axis of a convex lens (f = 15 cm) at a distance of 30 cm from it. A glass plate (μ = 1.50) of thickness 1 cm is placed on the other side of the lens perpendicular to the axis. Locate the image of the point object.

Answer 1

Given :

Focal length of lens =f=15cm

u= 30cm

glass plate (μ = 1.50)

t= thickness of glass plate = 1cm

From lens formula :

1/f=1/v-1/u

1/v=1/f+1/u

=1/15 -1/30

=2-1/30

v=30cm

therefore image of object will be formed at a distance of 30cm to the right side of lens.

Δt=[1-1/μg]xt

=1-2/3 =1/3= 0.33cm

Image of object will be formed at 30+0.33=30.33cm from lens

Answer 2

The image will be formed at 30 + 0.33 = 30.33 cm from the lens on right side.