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Grade 12th pass10 grade science

A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the lens if the image is equal to the size of the object? Also find the power of the lens.

Profile image of Harshit Singh
5 Years agoGrade 12th pass
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1 Answer

Profile image of Pawan Prajapati
5 Years ago
v = + 50 cm Since image is real and of same size. The position of image should be double the focal length. Hence, the object should be at 2f. V = 2f = 50, f = 25 cm. Power = 1/f = 100/25 = 4D