Required Practical: Investigating Reflection & Refraction Flashcards

All 4 cards in this deck

What are the steps to investigate the refraction of light by a glass block (RP9)?
e.g. an angle of incidence of 40°

1. Draw round the block on paper and draw a normal where the ray will enter
2. Shine a narrow ray in at 40° to the normal and mark the ray going in and coming out with dots
3. Remove the block, join the dots and measure the angle of refraction from the normal with a protractor: e.g. 25°

Why should the ray from the ray box be as narrow as possible in RP9?

It is harder to judge the centre of a wider ray, which gives a larger uncertainty (more random error) in the angles measured.

What are the steps to estimate the uncertainty in a set of repeated angle measurements?
e.g. angles of refraction 28°, 25° and 22°

1. Find the range: $28 - 22 = 6$
2. Halve it: $6 \div 2 = 3$
3. Uncertainty $= \pm 3°$

Why is the room darkened when doing RP9 with a ray box?

The light ray is easier to see, so its path can be marked and its angle measured more accurately.