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Two thin lenses of focal lengths 20cm an...

Two thin lenses of focal lengths 20cm and 25cm are placed in contact. The effective power of the combination is

A

5 D

B

9 D

C

45 D

D

none of these

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The correct Answer is:
B
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MCGROW HILL PUBLICATION-REFRACTION OF LIGHT-HIGHER ORDER THINKING QUESTIONS
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