Physics - Waves 2

Experiment for investigating the refraction of light and calculating the refractive index of glass

Draw around glass block on piece of paper.

Draw on the normal and the incident rays you want to use

Put block back in line.

Aim light from light block along incident rays and mark up against the block where they exit.

Take away block

Connect up lines and from that measure the angle of refraction.

Calculate sin i and sin r.

Plot them against each other on a graph.

Draw line of best fit

Find gradient which = refractive index (n)

Formula for refractive index using angle of incidence and angle of refraction

n = sin i / sin r

Rule of refractice index

Can never be less than 1 which is the refractive index of air

Total internal reflection (TIR)

When going from a high refractive index to a low refractive index when the angle of incidence is higher than the critical ingle so it reflects instead of refracts

Critical angle =

The angle of incidence when the angle of refraction is 90°. Only happens when going from a high refractive index to a low refractive index

Equation linking refractive index and critical angle

n = 1 / C