Question

In determining the refractive index of a glass slab using a travelling microscope, the following readings are tabulated:
(a) Reading of travelling microscope for ink = 8.123 cm
(b) Reading of travelling microscope for ink through glass slab = 6.123 cm
(c) Reading of travelling microscope for chalk dust on glass slab = 8.123 cm
From the data, the refractive index of a glass slab is:}

• A. 1.199
• B. 1.398
• C. 1.500
• D. 1.569

Hint:

To calculate the refractive index of a material, divide the thickness measured in air by the thickness measured through the medium.

Answer 1

The Correct Option is C

The refractive index \( n \) of a glass slab can be calculated using the formula: \[ n = \frac{\text{Thickness of the slab in air}}{\text{Thickness of the slab in the medium}} \] From the data, the thickness of the glass slab in air is \( 8.123 \, \text{cm} \), and the thickness of the slab in the medium is \( 6.123 \, \text{cm} \). So, the refractive index \( n \) is: \[ n = \frac{8.123}{6.123} = 1.500 \] Thus, the refractive index of the glass slab is \( 1.500 \), corresponding to option (3).