A lens of power +2 text{ D} is placed in cont | vedclass

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(C) When two thin lenses are placed in contact, the equivalent power $P$ of the combination is the algebraic sum of the individual powers:$P = P_1 + P

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$A$ convergent lens of focal length $100 	ext{ cm}$

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(C) When two thin lenses are placed in contact, the equivalent power $P$ of the combination is the algebraic sum of the individual powers:$P = P_1 + P_2$Given $P_1 = +2 	ext{ D}$ and $P_2 = -1 	ext{ D}$, the equivalent power is:$P = (+2 	ext{ D}) + (-1 	ext{ D}) = +1 	ext{ D}$Since the power is positive, the combination behaves as a convergent (convex) lens.The focal length $f$ is given by:$f = \frac{100}{P} 	ext{ cm} = \frac{100}{+1} 	ext{ cm} = +100 	ext{ cm}$Thus, the combination acts as a convergent lens of focal length $100 	ext{ cm}$.

$A$ lens of power $+2 \text{ D}$ is placed in contact with a lens of power $-1 \text{ D}$. The combination will behave like:

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