Question

A 3cm tall object is placed perpendicular to the principal axis of convex lens of focal length 15cm. The distance of the object from the lens is 30cm. Find the nature position and size of the image?​

Answer 1

Answer:

Given :

• Object Height (Ho) = 3 cm

• Object Position (u) = - 20 cm

• Focal length (f) = 30 cm

• Convex Lens

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To Find :

• Image Position , size and nature

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Solution :

Use lens formula

⇒1/f = 1/v - 1/u

⇒ 1/v = 1/f + 1/u

⇒ 1/v = 1/(30) + 1/(-20)

⇒ 1/v = 1/30 - 1/20

⇒ 1/v = (2 - 3)/60

⇒ 1/v = -1/60

⇒ v = - 60 cm

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⇒m = v/u = H'/Ho

⇒-60/-20 = H'/3

⇒3 = H'/3

⇒H' = 3 * 3

⇒ H' = 9 cm

Explanation: