Ray Optics Question 1
Question 1 - 2024 (01 Feb Shift 1)
The distance between object and its 3 times magnified virtual image as produced by a convex lens is $20 \mathrm{~cm}$. The focal length of the lens used is $\mathrm{cm}$.
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Answer: (15)
Solution:
$v=3 u$
$v-u=20 \mathrm{~cm}$
$2 u=20 \mathrm{~cm}$
$u=10 \mathrm{~cm}$
$\frac{1}{(-30)}-\frac{1}{(-10)}=\frac{1}{f}$
$f=15 \mathrm{~cm}$
