Ray Optics Test...

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

A student can distinctly see the object upto a distance 15 cm. He wants to see the black board at a distance of 3 m. Focal length and power of lens used respectively will be

Image is formed for the short sighted person at

A man can see the objects upto a distance of one metre from his eyes. For correcting his eye sight so that he can see an object at infinity, he requires a lens whose power is

A man can see the object between 15 cm and 30 cm. He uses the lens to see the far objects. Then due to the lens used, the near point will be at

The far point of a myopia eye is at 40 cm. For removing this defect, the power of lens required will be

Image formed on retina of eye is proportional to

If the distance of the far point for a myopia patient is doubled, the focal length of the lens required to cure it will become

A person uses a lens of power + 3 D to normalize vision.Near point of hypermetropic eye is

In an eye-piece, field lens and eye lens have focal lengths 7.5 cm and 7.3 cm. To eliminate spherical aberration, distance between them would be