Questions in Ray Optics and Optical Instruments

Select	Question
	A person suffering from 'presbyopia' (myopia and hyper metropia both defects) should use
	A person who can see things most clearly at a distance of 10 cm. Requires spectacles to enable to him to see clearly things at a distance of 30 cm. What should be the focal length of the spectacles
	Far points of myopic eye is 250 cm, then the focal length of the lens to be used will be
	A man can see clearly up to 3 metres. Prescribe a lens for his spectacles so that he can see clearly up to 12 metres
	A satisfactory photographic print is obtained when the exposure time is 10 sec at a distance of 2 m from a 60 cd lamp. The time of exposure required for the same quality print at a distance of 4 m from a 120 cd lamp is
	A person can not see the objects clearly placed at a distance more than 40 cm. He is advised to use a lens of power
	A person uses a lens of power + 3D to normalise vision. Near point of hypermetropic eye is
	A defective eye cannot see close objects clearly because their image is formed
	Image formed on retina of eye is proportional to
	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