A camera objective has an aperture diameter d . If the aperture is reduced to diameter `d//2` the exposure time under identical conditions of light should be made

If we double the aperture of a photographic camera, the new exposure time should be :

A lens having focal length f 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 lens having focal length f 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 metallic sphere of diameter D has a cavity of diameter d at its centre. If the sphere is heated, the diameter of the cavity will:

If the aperture of a camera is halved then for the given illumination of the object the exposure time should :

The camera lens has an aperture of f and the exposure time is 1/60 s. What will be the new exposure time if the aperture become 1.4 f?

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.