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When two thin lenses of focal lengths fi...

When two thin lenses of focal lengths fi and f, are kept coaxially and in contact, prove that their cobined focal length "f" is given by :
`(1)/(f)=(1)/(f_(1))+(1)/(f_(2))`

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To prove that the combined focal length \( f \) of two thin lenses in contact with focal lengths \( f_1 \) and \( f_2 \) is given by the formula: \[ \frac{1}{f} = \frac{1}{f_1} + \frac{1}{f_2} \] we will follow these steps: ...
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