Question

hard hai yaro atta hai toh dekho

find power of covex lens which forms a real inverted image of magnification -1 of an object placed at 20 cm from its optical center .........

Answer 1

yarr physics ki topper hu

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the image is real and inverted

hence the image formed would be on 2f1  

therefore, u=20

m=-v/u

m=-1 (given)

therefore , v= -20

1/f = 1/v- 1/v

1/f = 1/-20 - 1/20

1/f= 1/10

f=10cm

f=0.1m

p=1/f

p= 1/0.1

p = 10 D

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hope it helps.......

here is your answer mate

Answer 2

dear mate heres your answer

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hence the image formed would be on 2f1  

therefore, u=20

m=-v/u

m=-1 (given)

therefore , v= -20

1/f = 1/v- 1/v

1/f = 1/-20 - 1/20

1/f= 1/10

f=10cm

f=0.1m

p=1/f

p= 1/10

p = 0.1 D