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 `(mu= 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.

Explanation

Due to lens, image is formed at formed at distance 30 cm on the other side.
Due to glass slab, shift`=t(1-(1)/(mu))=1(1-(1)/((3//2)))=(1)/(3)cm`
Final image is formed at distance `=30+(1)/(3)=30.33cm` from lens
(b). `(1)/(f)=(1)/(v)-(1)/(u)=(1)/(10)-(1)/(-40)=(5)/(40)=(1)/(8)impliesf=8cm`
Shift due to slab `=3(1-(1)/((3)/(2)))=1cm`
Image by lens should be formed at distance `=10-1=9cm`
`(1)/(v)-(1)/(u)=(1)/(f)implies(1)/(9)-(1)/(-x)=(1)/(8)impliesx=72cm`