Question

A microscope is focussed on a mark on a piece of paper and then a slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?

Options

• 1 cm downward

• 4.5 cm downward

• 2 cm upward

• 1 cm upward

Answer 1

1 cm upward

Explanation:

Normal shift,

d = `"t"(1 - 1/(""^amu_"g")) = 3(1 - 1/1.5)` = 1 cm