A microscope is focused on a mark on a table, when the mark is covered by a plate of glass 2m thick, the microscope has to be raised 0.67cm for the mark to be once more in focus. Calculate the refractive index.
1.50
1.68
2.58
1.82
Correct answer is A
R = th = 2cm, d = 0.67cm
| n | = | R
A |
= | R
R.d |
= | 2
2-0.67 |
= | 1.52 |