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प्रश्न
A 5 cm tall object is placed perpendicular to the principle axis of a convex lens of focal length 12 cm. The distance of the object from the lens is 8 cm. Using the lens formula, find the position, size and nature of the image formed.
उत्तर
u = −8 cm
f = 12 cm
h = 5 cm
Now lens formula is
`1/v-1/u=1/f`
Putting Values
`1/v=1/12+1/-8`
`=1/12-1/8`
`=(2-3)/24=-1/24=>v=-24`cm
Thus, image is formed 24 cm on the left of convex lens i.e. on the side of the object.
Now magnification is `m =v/u=h^'/h`
`(-24)/(-8)=h^'/5`
h′ = 15 cm (Positive)
The height of the image is 15 cm which is 3 times larger than the height of object.
Thus, we can say image is virtual, enlarged and erect.
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