Question

A central portion of width d = 0.5 mm is cut out of convex lens of focal length 10 cm. Both halves are tightly fitted against each other. A point object is placed at distance 15 cm from lens then

• A. We get single real image of object
• B. We get two real images of object
• C. Distance of image/images from object is 45 cm
• D. Separation between images is 1.5 mm

Answer 1

Answer: (B), (C), (D)

The correct options are
B We get two real images of object
C Distance of image/images from object is 45 cm
D Separation between images is 1.5 mm


Each piece will form its own image.
$\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\Rightarrow \frac{1}{10}=\frac{1}{v}+\frac{1}{15}$

$\frac{1}{10}-\frac{1}{15}=\frac{1}{v}\Rightarrow v=30cm$

$\frac{I}{0}=\frac{v}{u}\Rightarrow I=0.25\times \frac{30}{15}=0.5mm$
The distance between the images is $0.5+2\left(0.25\right)+0.5=1.5mm$