Two thin similar convex glass pieces are joined together front to front with its rear portion silvered such that a sharp image is formed 20 cm from themirror. When the air between the glass pieces is replaced by water (U water= 4/3), then the imageformed from the mirror is at a distance of(1) 8 cm(3) 6 cm(2) 10 cm(4) 12 cm

Q. Two thin similar convex glass pieces are joined together front to front with its rear portion silvered such that a sharp image is formed 20 cm from the mirror. When the air between the glass pieces is replaced by water (${\mu }_w=4/3$), then the image formed from the mirror is at a distance of

Q. Two thin similar convex glass pieces are joined together front to front with its rear portion silvered such that a sharp image is formed $20\text{cm}$ from the mirror. When the air between the glass pieces is replaced by water $({\mu }_w=4/3)$, then the image formed from the mirror is at a distance of
[Assume, glass pieces have same refractive index as water]

Q. Two thin similar convex glass pieces are joined together front to front, with its rear portion silvered such that a sharp image is formed 0.2 m for an object at infinity. When the air between the glass pieces is replaced by water $⟮\mu =\frac{4}{3}⟯$, find the position of image.

Q. Comprehension
Two thin similar spherical glass pieces of radius $40\text{cm}$ are joined together front to front with rear portion of one piece silvered and the combination of glass pieces is placed at a distance $60\text{cm}$ from a screen. A point object is placed on the optical axis of the combination at the mid point of the line joining this combination and screen. Initially there is air between glass pieces as well as between combination and screen.


If air between the glass pieces is replaced by water $(\mu =\frac{4}{3})$, the new system (combination of glass pieces and water) behaves like :

Q. Comprehension
Two thin similar spherical glass pieces of radius $40\text{cm}$ are joined together front to front with rear portion of one piece silvered and the combination of glass pieces is placed at a distance $60\text{cm}$ from a screen. A point object is placed on the optical axis of the combination at the mid point of the line joining this combination and screen. Initially there is air between glass pieces as well as between combination and screen.


The distance through which the object must be displaced so that the sharp image is again formed on screen is: