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Powers of two thin lenses from their combined power in contact and when separated

The same question, asked 2 times: 2 May 2023 S1*, 14 May 2024 S1. Every wording below, oldest first.

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  1. Question 1

    2 May 2023 S1

    14
    Two thin lenses have a combined power of +9 D+9\,D. When they are separated by a distance of 20 cm, their equivalent power becomes +275 D+\frac{27}{5}\,D. The power of both the lenses in dioptre are respectively

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  2. Question 2

    14 May 2024 S1

    1
    A combination of two thin lenses in contact have power +10 D. The power reduces to +6 D when the lenses are 0.25 m apart. The power of individual lens is

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