Home
Class 12
PHYSICS
A 20cm thick glass slab of refractive in...

A `20cm` thick glass slab of refractive index `1.5` is kept in front of a plane mirror. Find the position of the image (relative to mirror) as seen by an observer through the glass slab when a point object is kept in air at a distance of `40 cm` from the mirror.

Text Solution

Verified by Experts

Shifting in object due to glass slab x =`d(1-(1)/(mu)) = 20[1-(1)/(1.5)] = (20)/(3) "cm"`
Distance of object from mirror (as seen by mirror) =`40 - (20)/(3) = (100)/(3) "cm"`
Image will be formed at a distance `(100)/(3)` cm from mirror `M`.
Shifting in image due to glass slab = `(20)/(3)` cm
So distance of image from mirror = `(100)/(3) - (20)/(3) = (80)/(3) "cm"`

Distance of image from the actual plane mirror is independent of separation b between glass slab and mirror. If the distance is more than brightness of image will be less.
Promotional Banner

Topper's Solved these Questions

  • GEOMETRICAL OPTICS

    ALLEN|Exercise SOME WORKED OUT EXAMPLES|84 Videos

  • GEOMETRICAL OPTICS

    ALLEN|Exercise EXERCISE -01|65 Videos

  • CURRENT ELECTRICITY

    ALLEN|Exercise All Questions|427 Videos

  • GRAVITATION

    ALLEN|Exercise EXERCISE 4|9 Videos

Similar Questions

Explore conceptually related problems

A slab of glass, of thickness 6 cm and refractive index mu =1.5 is placed in front of a concave mirror as shown in the figure. If the radius of curvature of the mirror is 40 cm and the reflected image coincides with the object, then the distance of the object from the mirror is

A flat glass slab of thickness 6 cm and index 1.5 is placed in front of a plane mirror. An observer is standing behind the glass slab and looking at the mirror. The actual distance of the observer from the mirror is 50 cm. The distance of his image from himself, as seen by the observer is

A point object (A) is kept at a distance (L) from a convex mirror on its principal axis. A glass slab is inserted between the object and the mirror with its refracting surfaces perpendicular to the principal axis of the mirror. The thickness of the slab is 6 cm and its refractive index is (3)/(2) . The image formed after refraction through the slab, reflection from the mirror followed by refraction through the slab is a virtual image at a distance of 10 cm from the pole of the mirror (on its principal axis). Consider paraxial rays only and calculate the distance (L) of the object from the mirror. Focal length of the mirror is f = 20 cm .

A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is

A glass slab of thickness 3cm and refractive index 1.5 is placed in front of a concave mirror of focal length 20cm. Where should a poing object be placed if it is to image on to itself?

An object is placed 21 cm in front of a concave mirror of radius of curvature 10cm. A glass slabe of thickness 3cm and refractive index 1.5 is then placed close to the irror in the space between the object and the mirror. The distance of the near surface of the slabe from the mirror is 1cm. The final image from the mirror will be formed at