A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 18 cm at a distance of 12 cm from it. Use lens formula to determine the position, size and nature to the image formed.
According to the question;
Object distance = -12cm;
Image distance = v;
Focal length = 18cm;
By lens formula;
⇒ v = -36cm.
Therefore, image is formed at 36 cm in front of lens.
Now;
Height of object h1= 5cm;
Magnification = 
= 
Putting values of v and u
Magnification = 
⇒ 
⇒ 
Height of image is 15 cm.
Thus, the image is virtual, enlarged, and erect and three times the size of object.
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