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A double convex lens of glass of refractive index `1.6` has its both surfaces of equal radii of curvature of `30 cm `each. An object of height `5 cm` is placed at a distance of `12.5 cm` from the lens. Calculate the size of the image formed. |
Answer» Correct Answer - `10 cm` Here, `mu = 1.6, R_(1) = 30 cm, R_(2) = - 30 cm` `h_(1) = 5 cm, u = - 12.5 cm, h_(2) = ?` `(1)/(f) = (mu - 1)((1)/(R_(1)) - (1)/(R_(2)))` `= (1.6 - 1)((1)/(30) + (1)/(30)) = (0.6)/(15)` `f = (15)/(0.6) = 25 cm` As `(1)/(v) - (1)/(u) = (1)/(f)` `:. (1)/(v) = (1)/(f) + (1)/(u) = (1)/(25) - (1)/(12.5) = (-1)/(25)` `v = - 25 cm` As `m = (h_(2))/(h_(1)) = (v)/(a) :. (h_(2))/(5) = (- 25)/(-12.5) = 2` `h = 10 cm` |
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