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The focal length of a convex lens is 20 cm . If an object of height 4 cm is placed at 30 cm from the lens , find the position, nature and size of the image . |
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Answer» SOLUTION :Data : Convex lens , `f=20` cm , `u=-30 cm , h_(1)=2 cm , v=? , h_(2) =? , M=?` `1/v =1/f + 1/u=1/(20 cm)+(1)/(-30CM)` `=(1)/(20 cm) -(1)/(30 cm)` `=(3-2)/(60 cm)=(1)/(60 cm)` `THEREFORE ` v=60 cm , v is positive. The image will be FORMED at 60 cm from the lens andon the other side of the lens with RESPECT to the object . It is a real image. |
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