Q. A microscope is focused on an ink mark on the top of a table. If we place a glass slab of 3 cm thick on it, how should the microscope be moved to focus the ink spot again? The refractive index of glass is 1.5.
A) 2 cm upwards
B) 2 cm downwards
C) 1 cm upwards
D) 1 cm downwards
Explanation
(c) Given, $n$ = 1.5, $h_{0}$ = 3
$n = \frac{h_{0}}{h_{1}}$
$1.5 = \frac{3}{h_{1}}$
$h_{i}\ = \frac{3}{1.5} = 2\ cm$
Hence, 3-2 = 1 cm upwards.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.