Question

an object is placed at a distance od 10cm from m the concave lens of focal lenght of 20cm. fibd the position of image. jai hc verma
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Answer 1

Given :

• Object is placed at (u) = -10cm
• Focal lenght of lens (f) = -20cm

To Find :

• Position of image

Formula Used :

$\bullet\underline{\boxed{\sf \dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}}}$

Solution :

⟹ 1/-20 = 1/v - (1/-10)

⟹ 1/-20 = 1/v + 1/10

⟹ 1/v = 1/-20 -1/10

⟹ 1/v = 10-(-20)/-20×10

⟹ 1/v = 30/-200

⟹ v = -20/3 cm

$\bullet$ Image is formed between F and infinity

$\bullet$ Virtual , erected , diminished

Answer :

Image is formed as Distance (v) = -20/3 cm