S2 Science: Reflection, Refraction And Dispersion Of Light (Paper 2 (intermediate))

S2 Science: Reflection, Refraction and Dispersion of Light (Paper 2 (intermediate))

2026-11-14

← Back to the Secondary Science chapter index

Tutor Prep Guide · The law of reflection and plane mirror images, judging refraction direction, prism dispersion and total internal reflection

S2 Science: Reflection, Refraction and Dispersion of Light (Paper 2 (intermediate))

This paper links refractive index with speed and wavelength, and practises dispersion and apparent depth.

Direct answers　The refractive index is the ratio of the vacuum speed to the speed in the medium, while the frequency stays fixed and the speed and wavelength change together.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: S2 Science: Reflection, Refraction and Dispersion of Light
Level	S2

02　Questions (10 items)

FoundationWhite light passes through a glass prism and spreads into seven colours. What is this called?
FoundationWhich colour is deviated least by a prism?
FoundationLight passes from glass into air. Is the angle of refraction larger or smaller than the angle of incidence?
IntermediateA glass has refractive index 1.5 and light travels at 3×10⁸ m/s in vacuum. What is the speed of light in the glass?
IntermediateIf the angle of incidence is 48.6 degrees and the refractive index is 1.5, what is the angle of refraction?
IntermediateDoes the frequency of light change when it enters glass from air?
ChallengeLight of wavelength 600 nm in air enters glass of refractive index 1.5. What is its wavelength in the glass?
ChallengeA pool is 2.0 m deep and water has refractive index 1.33. About how deep does it look?
ChallengeHow many refractions occur as light passes through a prism?
Error redoA student says the angle of refraction is always smaller, so light always bends towards the normal. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	Dispersion	Each colour has a slightly different refractive index in glass, so each is deviated by a different amount.
2	Red	Red has the smallest refractive index so it bends least, while violet bends most.
3	Larger	Going from a denser to a less dense medium the light speeds up and bends away from the normal.
4	2×10⁸ m/s	Divide the vacuum speed by the refractive index.
5	30 degrees	Divide sin 48.6 degrees by 1.5 to get 0.5, whose angle is 30 degrees.
6	No	Frequency is fixed by the source; the speed and wavelength change instead.
7	400 nm	Divide 600 by 1.5 to get 400 nm while the frequency stays the same.
8	About 1.5 m	Apparent depth is real depth divided by the refractive index.
9	Two	Once on entering and once on leaving, and both deviations add up to separate the colours.
10	That only holds when light enters a denser medium; going from water into air the angle of refraction is larger and light bends away from the normal.	Decide first which medium is denser, then work out the direction of bending.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

For light questions ask three things: whether angles are measured from the normal, whether light goes from a denser to a less dense medium or the other way, and how many refractions occur.Tutor Registration →

Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.