If aperture of lens is halved then image will be

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

Aperture of lens of a camera is f and its exposure time is (1)/(60) s. If aperture becomes 1.4 f, then what will be the exposure time ?

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 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 lens having focal length f and aperture of diameter d forms an image od intensity I, Aperture of diameter d//2 in central region of lens is covered by a block paper. Focal length of lens intensity of image now will be respectively :