JEE Main & Advanced
Physics
Ray Optics
Sample Paper
Topic Test - Refraction of Light Through Curved Surfaces
question_answer
A thin linear object of size 1 mm is kept along the principal axis of a convex lens of focal length 10 cm. The object is at 15 cm from the lens. The length of the image is:
A)1 mm
B)4 mm
C)2 mm
D)8 mm
Correct Answer:
B
Solution :
[b] \[\frac{1}{10}=\frac{1}{V}=-\frac{1}{(-15)}\Rightarrow v=+30\,cm\] for small object \[dv=\frac{{{v}^{2}}}{{{u}^{2}}}du={{\left( \frac{30}{15} \right)}^{2}}\times 1=4\,mm\]