Home
Class 12
PHYSICS
Two identical glass (mu(g) = (3)/(2)) eq...

Two identical glass `(mu_(g) = (3)/(2))` equiconvex lenses of focal length f are kept in contact. The space between the two lenses is filled with water `(mu_(w) = (4)/(3))`. The focal length of the combination is

A

f/3

B

f

C

4f/3

D

3f/4

Text Solution

Verified by Experts

The correct Answer is:
D

For equiconvex lens
`(1)/(A)=((3)/(2)-1)((1)/(R)-(1)/(-R))`
`(1)/(f)=(1)/(2)*(2)/(R)`
`R=f`
For 2nd lens `(1)/(f_(2))=((4)/(3)-1)((1)/(-f)-(1)/(-f))`
`(1)/(f_(2))=(1)/(3)xx(2)/(-f)`
`f_(2)=(-3f)/(2)`
For combination
`(1)/(f')=(1)/(f_(1))+(1)/(f_(2))+(1)/(f_(3))`
`=(1)/(f)+(2)/(-3f)+(1)/(f)`
`(1)/(f')=(3-2+3)/(3f)=(4)/(3f)`
`f'=(3f)/(4)`
Promotional Banner

Similar Questions

Explore conceptually related problems

Two identical glass (mu_(g)=3//2) equiconvex lenses of focal length f are kept ini contact. The space between the two lenses is filled with water (mu_(w)=4//3) . The focal length of the combination is

Two identical glass (mu_(g)=3//2) equi- convex lenses of focal length f each are kept in contact. The space between the two lenses is also filled with water (mu_(g)=4//3). The focal length of the combination is

Two identical glass (mu_(g)=3//2) equi- convex lenses of focal length f each are kept in contact. The space between the two lenses aiisolfilled with water (mu_(g)=4//3). The focal length of the combination is

Two concave lenses L_1 and L_2 are kept in contact with each other. If the space between the two lenses is filled with a material of smaller refractive index, the magnitude of the focal length of the combination

Two lenses of power 15D and -3D are placed in contact. The focal length of the combination is a

Two thin lenses of focal lengths f_(1) and f_(2) are in contact. The focal length of this combination is

A thin equiconvex lens (mu=3//2) of focal length 10cm is cut and separated and a material of refractive index 3 is filled between them. What is the focal length of the combination?

Two lenses of power -15D and +5 D are in contact with each other. The focal length of the combination is

A convex lens of focal length f_(1) is kept in contact with a concave lens of focal length f_(2) . Find the focal length of the combination.

Two convex lenses of focal lengths 0.3m and 0.05m are used to make a telescope. The distance kept between the two is