Refraction of Light: JAMB Physics Questions, Answers & Notes

What Refraction of Light covers in the JAMB Physics syllabus

Refraction is the bending of light when it changes speed passing between media. Entering a denser medium it slows and bends toward the normal; entering a less dense medium it speeds up and bends away. Snell's law gives the refractive index n = sin i / sin r = (speed in vacuum)/(speed in medium). Refraction explains a 'bent' stick in water and a pool looking shallower. Beyond the critical angle, light in the denser medium undergoes total internal reflection — used in optical fibres and prism periscopes. A prism disperses white light into a spectrum; violet bends most, red least (this also forms rainbows).

For Refraction of Light, JAMB expects you to be able to:

• Explain refraction and apply Snell's law and refractive index
• Explain the critical angle and total internal reflection with applications
• Describe dispersion of white light and the spectrum

Key facts & revision notes: Refraction of Light

These are the recurring points our Refraction of Light questions test — revise them until each feels automatic, then practise the questions above to lock them in.

• Refraction occurs because light changes speed when it enters a different medium, bending its path.
• Entering a denser medium (slower), light bends toward the normal.
• Entering a less dense medium (faster), light bends away from the normal.
• Snell's law: refractive index n = sin i / sin r.
• Refractive index n = sin(angle of incidence) / sin(angle of refraction).
• n = sin i / sin r = 0.866/0.5 = 1.73.
• n = (speed of light in vacuum) ÷ (speed of light in the medium).
• Light from the submerged part refracts at the water surface, making the stick look bent.
• Refraction of light leaving the water makes the pool bed appear raised, so the pool looks shallower.
• The critical angle is the incidence angle (in the denser medium) that gives a 90° refraction angle.
• When the incidence angle exceeds the critical angle, light is totally reflected back into the denser medium.
• Optical fibres and prism periscopes/binoculars rely on total internal reflection.
• Dispersion is the separation of white light into the spectrum of colours by a prism.
• Violet has the shortest wavelength and is refracted (bent) the most; red is bent the least.
• The spectrum is the band of colours (red to violet) formed by dispersion of white light.
• Rainbows form when sunlight is refracted, dispersed and internally reflected within raindrops.
• 50° exceeds the critical angle of 42°, so total internal reflection occurs.
• The larger the angle of incidence, the greater the bending; light along the normal is not bent.
• At 0° incidence (along the normal), light passes straight through without changing direction.
• Red light has the longest wavelength, travels fastest in glass and is refracted the least.
• A change in speed at the boundary bends the ray.
• Going into a denser medium bends light toward the normal.
• n = c/v = (3×10⁸)/(2×10⁸) = 1.5.
• r is the angle of refraction.

Worked examples

Three Refraction of Light questions with the answer and a short explanation, so you can see how the topic is set before you practise the full set.

How Refraction of Light is tested in JAMB Physics

Our Refraction of Light bank holds 40 questions (2 easy, 25 medium, 13 hard). JAMB Physics typically returns to Refraction of Light year after year, so steady practice on this topic is high-value revision. Questions are multiple-choice with four options, and at UTME pace you get roughly 40 seconds each — which is why timed practice matters.

How to answer Refraction of Light questions

Work the stem first and predict the answer before you look at the options; then eliminate the ones that contradict the key facts above. Watch for “which is not…”, “all of the above” and “except” style stems, which are where rushed candidates lose easy marks on Refraction of Light. If a calculation or a precise definition is involved, work it from first principles rather than guessing from a half-remembered rule. When two options look right, re-read the stem for the qualifier that separates them — JAMB rarely repeats an option by accident. If you are still unsure, eliminate the two weakest choices to lift your odds, flag the question, and move on; never burn a full minute on one Physics item when the exam gives you about forty seconds each. Then come back to flagged questions with whatever time remains. The single most reliable way to get faster at Refraction of Light is repeated timed practice, so use the button above until the recurring patterns feel automatic.

Common mistakes to avoid in Refraction of Light

The errors that cost marks on Refraction of Light are usually careless rather than conceptual: misreading a negative stem, confusing two similar terms, or rushing a definition you actually know. Candidates also over-rely on “expo” and last-minute cramming instead of understanding the topic — which fails the moment JAMB rephrases a familiar idea. Treat every option as a claim to be checked against the facts above, keep your working tidy for any calculation, and don’t change a considered answer on a hunch. Above all, revise Refraction of Light actively by answering questions, not just by re-reading notes — recall under time is what the exam rewards.

Frequently asked questions

Is Refraction of Light part of the JAMB Physics syllabus?

Yes. Refraction of Light is a recognised topic in the JAMB Physics syllabus, covering explain refraction and apply Snell's law and refractive index. You should be able to recall its key facts and apply them to multiple-choice questions.

How many Refraction of Light questions can I practise on Belmadeng?

There are 40 original, JAMB-standard Refraction of Light questions in our free bank, each with the correct answer and a worked explanation. You can practise them untimed or as a timed test.

What are the most important points to know about Refraction of Light?

Refraction is the bending of light when it changes speed passing between media. Entering a denser medium it slows and bends toward the normal; entering a less dense medium it speeds up and bends away. Snell's law gives the refractive index n = sin i / sin r = (speed in vacuum)/(speed in medium). Ref…

How do I answer Refraction of Light questions quickly in JAMB?

Read the stem carefully, eliminate clearly wrong options, and match the remaining choices to the key facts for Refraction of Light. Practising timed Refraction of Light questions builds the speed you need for UTME's pace of about 40 seconds per question.

Are these JAMB Physics Refraction of Light questions past questions or original?

They are original questions written to JAMB (UTME) standard and mapped to the official syllabus — not reproduced past papers. This keeps them legal to use freely while closely mirroring how the real exam tests the topic.

Where can I practise Refraction of Light questions free without signing up?

Right here — tap “Start Refraction of Light practice” on this page to begin instantly. Belmadeng's CBT practice is completely free and needs no sign-up, download or subscription.

About these questions: original, JAMB-standard items written from the official UTME Physics syllabus (last reviewed 2026-09-18). Belmadeng is an independent study platform and is not affiliated with JAMB. Spotted an error? Use the report link.