An object of height 1 cm is placed in front of a concave lens of focal length 40cm . If the object distance is 60 cm , find the position and height of the image .

An object of height 1 cm is placed in front of a concave lens of focal

1.	An object of height 1 cm is placed in front of a concave lens of focal length 40cm . If the object distance is 60 cm , find the position and height of the image .
Answer» SOLUTION :Data : `f=-40cm `(concave lens), `U=-60 cm, h_(1)=1 cm , v=?,h_(2)=?` `(i) 1/f =1/v-1/utherefore 1/v=1/f+1/u` `therefore 1/v=(1)/(-40cm)+(1)/(-60 cm) =-((1)/(40cm)+(1)/(60cm))` `=-((3+2)/(120 cm))=-(5)/(120)cm` `therefore v=-(120)/(5)cm =-25 cm` The IMAGE is FORMED at 24 cm from the lens . It is on the same side as the object . (II)`(h_(2))/(h_(1))=(v)/(u) therefore h_(2)=v/u h_(1)` `therefore h_(2)=((-24 cm)/(-60))xx1 cm =0.4xx 1 cm =0.4 cm` The heigth of the image is 0.4 cm