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InterviewSolution
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There is a convex lens of focal length 20 cm and a point object is placed at a distance 30 cm to the left of the lens. Radius of the lens is 5 cm. A person has placed eye at the right of lens at a distance 75 cm from the lens and at a height h below the principal axis. What can be the maximum value of h so that person is able to see the image ? |
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Answer» 1.25 cm `(1)/(v)-(1)/(u)=(1)/(f)` `rArr""(1)/(v)-(1)/((-30))=(1)/(20)` `rArr""(1)/(v)=(1)/(20)-(1)/(30)=(3-2)/(60)` `rArr""v=+60cm` HENCE image is formed at a distance 60 cm to the right of the lens. Refer to the below given figure to calcualte height of eye below principal axis so that light RAY refracted from the top point of lens is able to pass through the eye so that image of the point object is visible to the person.  `(5)/(60)=(h)/(15)` `rArr""h=1.25cm` Hence, option (a) is correct. |
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