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MHT CET 2023 (10 May, Shift 2) · Combination of Lenses

Combination of Lenses question from MHT CET 2023 (10 May, Shift 2)

Q31MHT CET 2023 · 10 MAY · SHIFT 2Easy

Combination of Lenses

Two lenses of power $-15\text{ D}$ and $+5\text{ D}$ are in contact with each other. The focal length of the combination is

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Answer: (b)

For lenses in contact powers add: $P = P_1 + P_2$ .
$P = -15 + 5 = -10\text{ D}$
$f = \frac{1}{P} = -\frac{1}{10}\text{ m} = -10\text{ cm}$
So the answer is (b) $-10\text{ cm}$ .

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