How do you determine the refractive index of a glass slab using a travel microscope?

How do you determine the refractive index of a glass slab using a travel microscope?

Place the glass slab of least thickness over the mark P. Raise the microscope upwards and focus it on the image P1 of the cross-mark. Note the reading (R2) on the vertical scale as before (Step 7). Sprinkle a few particles of lycopodium powder on the surface of the slab.

What is the refractive index of glass slab?

around 1.5
The refractive index of a glass slab is right around 1.5.

What is the theory of travelling microscope?

A travelling microscope is an instrument for measuring length with a resolution typically in the order of 0.01mm. It is used in laboratories to measure the refractive index of flat specimens using the geometrical concepts of ray optics (Duc de Chaulnes’ method).

Why Lycopodium powder is spread over the glass slab?

Hint: lycopodium powder is added to the surface so that the top of the slab can be focused. Also, placing a glass slab raises the image slightly. Travelling microscope is used to measure the real and apparent depth of the spot.

Why travelling microscope is called so?

Since this microscope can be taken outside of the laboratory for observations, therefore, it named travelling microscope.

What is the purpose of travelling microscope?

A travelling microscope is an instrument for measuring length with a resolution typically in the order of 0.01mm. It is designed to meet the requirements of research, colleges, schools and industrial laboratories. Travelling microscope is used for accurate measurement of the diameters of different objects.

How do you calculate a travel microscope?

1. The travelling microscope usually used has each mm divided equally into two halves.
2. So the smallest division on main scale will be 0.5 mm.
3. There are 50 divisions on the vernier scale.
4. Hence, the least count of travelling microscope is.

How is the refractive index of a glass slab determined?

To Determine Refractive Index of a Glass slab using a Travelling Microscope Travelling microscope is a compound microscope that is fitted on the vertical scale. It carries a vernier scale along the main scale and can be moved upward or downward. Below is an experiment to determine refractive index of a glass slab using a travelling microscope.

How to find the refractive index of light?

The refractive index with respect to the medium and air is given as: To get a sufficient amount of light, place the travelling microscope (M) near the window. To make the base of the microscope horizontal, adjust the levelling screw.

How are grey rays focussed without a glass block?

Without the glass block (grey rays) the cone of rays A C B originating from a point object are focussed by the microscope lens A B to form an image in the plane of the cross wires of the microscope at C ′.

Do you remove Parallax in a travelling microscope?

The parallax in a microscope should be removed properly. To avoid backlash error, the microscope should be moved upward. The scale used in the microscope might not be calibrated properly. The lycopodium powder layer on the glass slab might be thick. Q1.