Science (086) — AI-generated practice question

Observation: The red light will pass through the second prism but will not split further into more colours. It will emerge as red light only, possibly deviating in direction but remaining red.

Reason: White light is a mixture of seven colours (VIBGYOR). When the first prism disperses it, each colour is already separated. The red band is a single, pure component of the spectrum. Since it is not a mixture of different colours, the second prism has nothing further to disperse — it can only refract (bend) the red light, not split it. This was demonstrated by Newton, who showed that individual colours from a spectrum cannot be dispersed further by a second prism.

Source: Chapter 10, Section 10.4 — Dispersion of White Light by a Glass Prism

---

• The key idea examiners want: dispersion requires a mixture of colours; a single colour cannot be dispersed.
• Mention Newton's experiment — it directly supports this conclusion and is explicitly in the textbook.
• Avoid confusing refraction (bending, which still happens) with dispersion (splitting into colours, which does NOT happen here).
• 3 marks = observation (1) + reason with reference to dispersion/single colour (1) + Newton's link (1).