Home
Class 12
PHYSICS
A lens haivng focal length and aperture ...

A lens haivng focal length and aperture of diameter d forms an image of intensity `I`. Aperture of diameter `d/2` in central region of lens is covered by a black paper. Focal length of lens and intensity of image now will be respectively.

A

f and `1//4`

B

`3//4` and `1//2`

C

f and `31//4`

D

`f//2` and `1//2`

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Similar Questions

Explore conceptually related problems

A thin lens focal length f_(1) and its aperture has diameter d . It forms an image of intensity I . Now the central part of the aperture up to diameter (d)/(2) is blocked by an opaque paper. The focal length and image intensity will change to

A thin convex lens of focal length f, has its aperture of diameter d. It forms a real iomage of intensity I. The central part of the aperture is blocked by an opaque paper of diameter (d)/(2) . What is the focal length of the lens and the intensity of image formed by the lens ?

Power of a lens is + 3 D. What will be the focal length of the lens?

The focal length of a lens of power + 4D is :

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

A laser beam of 10mW power and wavelength 700nm has aperture of 3mm . If it is focused by a lens of focal length 5cm , the intensity of image is