Question

Describe an experiment to show lateral displacement in a glass slab. class eight I.C.S.E​

Answer 1

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With the help of a protractor draw one angle of 30° with the EN. Fix two pins P and Q on the ray of this angle, the distance between the pins should be more than 4-5 cm. Put the glass slab on the rectangular figure ABCD.

The distance between these two parallel rays is called lateral displacement

Answer 2

Answer:

Materials Required

A drawing board

4-6 all pins

White sheet of paper

Rectangular glass slab

A protractor

A scale

A pencil

Thumb pins

Procedure

Fix a white sheet on the soft drawing board using thumb pins.

Using a sharp pencil, draw the outline boundary of the glass slab, place it at the of the white paper.

Let ABCD be the rectangular figure obtained by drawing.

Mark point E on AB and draw a perpendicular EN and label it as a normal ray.

Draw one angle of 30° with the help of protractor with EN. Fix pins at P and Q at 4-5 cm on the ray that is obtained by the angle.

Place the glass slab on the rectangular figure ABCD.

To fix R and S, see through the glass slab of side CD, such that when seen through the glass slab, all the pins P, Q, R, and S should lie in a straight line.

Draw a small circle around the pins P, Q, R, and S and remove the pins.

Remove the glass slab.

Join points R and S such that it meets CD at point F. Draw a perpendicular N’M’ to CD at point F.

Using a pencil, join the points E and F.

Measure the angles formed at AB and CD, i.e, the incident angle, refracted angle, and emergent angle.

The lateral displacement is obtained by extending the ray PQ in a dotted line which is parallel ray to FRS.

Measure the lateral displacement.

Repeat the same procedure for angle 45° and 60°.

Ray Diagram

reflection of light through a rectangular glass slab