Question

An object is placed at a distance of $200cm$ from a combination of two equal lenses of equal power of $+1D$. The distance of the image of the object for system is:

• A. $33.33cm$
• B. $-33.33cm$
• C. $66.67cm$
• D. $40cm$

Answer 1

The correct option is D $40cm$

$P=P_1+P_2=2D$

$f=\frac{1}{2}m=50cm$

$\frac{1}{u}+\frac{1}{v}=\frac{1}{f}$

$\frac{1}{v}=\frac{1}{f}-\frac{1}{u}$

$=\frac{1}{50}-\frac{1}{-200}=\frac{1}{40}$

$v=40cm$