[tex]\Huge\underline{\underline{\color{purple}{\bf\pmb{Question}}}}\ \textless \ br /\ \textgreater \ [/tex]
A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed.
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Hope it helps uhh❤️ Dishant~
Answer:
According to the question,
Image distance, v=−15 cm (negative due to convex lens)
Focal length, f=−20 cm
Let the object distance be u.
By lens formula:
v1−u1=f1[4pt]
⇒−15 cm1−u1=−20 cm1[4pt]
⇒u1=20 cm1+−15 cm1[4pt]
⇒u1=60 cm3−4=60 cm−1[4pt]
⇒u=−60 cm
Therefore, object is placed at 60 cm away from the lens, on the same side as image.
Now,
Height of object, h1=5cm
Magnification, m=h1h2=u
Explanation:
Sorry for late answering Dear