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Two convex lenses of focal length f1 and...

Two convex lenses of focal length `f_1` and `f_2` are mounted coaxially separated by a distance. If the power of the combination is zero, the distance between the lenses is

A

`|f_1-f_2|`

B

`f_1+f_2`

C

`(f_1f_2)/(|f_1-f_2|)`

D

`(f_1f_2)/(f_1-f_2)`

Text Solution

Verified by Experts

The correct Answer is:
B
`d:` distance between lenses
`(1)/(F)=(1)/(f_1)+(1)/(f_2)-(d)/(f_1f_2)`
`P=(1)/(F)=0`
`(d)/(f_1f_2)=(1)/(f_1)+(1)/(f_2)=(f_2+f_1)/(f_1f_2)`
`d=f_1+f_2`
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Knowledge Check

  • Two convex lenses of focal lengths f_(1) and f_2 are separated co-axially by a distance d. The power of the combination will be one if

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