The combined focal length is F when a convex lens of focal length F₁ and concave lens of focal length F₂ is combined. The combination of these lenses will behave like a concave lens, if (a) F₁ > F₂ (b) F₁ < F₂ (c) F₁ = F₂ (d) F₁ ≤ F₂

Answer: (a). 1/F = 1/F₁ - 1/F₂ ( F₁, F₂ magnitudes). Concave behaviour needs 1/F F₂. So the answer is (a) F₁ > F₂.

The combined focal length is F when a convex lens of focal length F₁… | MHT CET 2026 (14 May, Shift 1)

Q3MHT CET 2026 · 14 MAY · SHIFT 1Medium

Combination of Lenses

The combined focal length is $F$ when a convex lens of focal length $F_1$ and concave lens of focal length $F_2$ is combined. The combination of these lenses will behave like a concave lens, if

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Answer: (a)

$\frac{1}{F} = \frac{1}{F_1} - \frac{1}{F_2}$ ( $F_1$ , $F_2$ magnitudes).
Concave behaviour needs $\frac{1}{F} < 0$ , i.e. $\frac{1}{F_1} < \frac{1}{F_2}$ , so $F_1 > F_2$ .
So the answer is (a) $F_1 > F_2$ .

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Combination of Lenses question from MHT CET 2026 (14 May, Shift 1)

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