Home
Class 11
PHYSICS
Two thin equiconvex lenses each of focal...

Two thin equiconvex lenses each of focal length 0.2 m are placed coaxially with their optic centres 0.5m apart. Then find the focal length of the combination.

A

`-0.4m`

B

0.4 m

C

`-0.1` m

D

0.1 m

Text Solution

Verified by Experts

The correct Answer is:
A
`(1)/(f) = (1)/(f_(1))+(1)/(f_(2)) -(d)/(f_(1)f_(2))`
`=(1)/(0.2)+(1)/(0.2) -(0.5)/(0.2xx0.2)`
`=5+5-0.5 xx 5 xx 5=-2.5`
`therefore f= -(1)/(2.5)=-0.4 m`
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS (MIRRORS, LENSES AND OPTICAL INSTRUMENTS)

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP|10 Videos

  • MEASUREMENTS

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP|10 Videos

  • REFRACTION OF LIGHT

    MARVEL PUBLICATION|Exercise Test Your Grasp|10 Videos

Similar Questions

Explore conceptually related problems

A convex lens of focal length 10.0 cm is placed in contact with a convex lens of 15.0 cm focal length. What is the focal length of the combination ?

A convax lens of focal length 10.0cm is placed in contact with a convex lens of 15.0cm focal length ,What is the focal length of the combination.

When two thin lenses are kept in contanct, the focal length of the combination is

Two concave lenses each of focal length 30 cm are placed in contact. What is focal of the compound lens ?

Two convex lenses of focal lengths 25 cm and 15 cm are placed in contact with each other. Find the focal length of combination.

Two concave lenses, eacb of focal length 30 cm are placed in contact with each other. Find the power of the combination.

A thin convex lens of focal length 10 cm is placed in contact with a concave lens of same material and of same focal length. The focal length of combination will be