Question

What is Refractive Index ? Write an activity to find refractive index
of glass. Draw the necessary diagram.
2+2+2=​

Answer 1

$\huge{\mathfrak{\purple{\boxed{\orange{\underbrace{\overbrace{\green{‡Answer‡}}}}}}}}$

$\large{\mathfrak{\orange{Refractive\:Index}}}$

The ratio between the speed of light in medium to speed in a vacuum is the refractive index. When light travels in medium other than the vacuum, the atoms of that medium continually absorb and re-emit the particles of light, slowing down the speed light.

$\large{\mathfrak{\orange{Activity}}}$

Using the apparatus shown in the diagram, direct a ray of light to enter the block near the middle of the longest side and to leave by the opposite side crossing directly from one side to the other. As you change the angle of the block to the light, notice the alterations in the direction of the emerging ray.

Draw round the edges of the block for one arrangement.

Mark the paths of the light outside the block with a few pencil dots.

Remove the block and draw in (with a ruler) the path of the ray through the block as a straight line.

Use arrows to show which way the light travelled.

Construct a normal where the ray enters the block and measure i and r.

Repeat for at least five different angles of incidence. Calculate the refractive index for the material of the glass block using Snell's law.

Refractive index,

$n \: = \frac{sin \: i}{sin \: r}$

2+2+2 = 6