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A convex mirror and convex lens of radius of curvature 20 cm are placed on same axis with 30 cm separation. A point-like object is placed at 20 cm from convex lens and its image by this combination is obtained at object. What will be focal length of convex lens ? |
Answer» Solution : `rArr`Here, RADIUS of curvature of convex lens `= O_2 C` = 20 CM Object DISTANCE OP = u = -25 cm Image distance OC = v = 30 + 20 = 50 cm `rArr` Lens formula `1/f= 1/v - 1/u = 1/50 + 1/25` `therefore1/f = (1+2)/(50) = 3/(50)` `thereforef = (50)/(3) = 16.67 cm ` |
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