Vapours

Contents & notes: what this topic covers

Under Vapours, the JAMB Physics syllabus expects you to study:

• 17. Vapours
• (i) unsaturated and saturated vapours;
• (ii) relationship between saturated vapour i. dis pressure (S.V.P) and boiling;
• (iii) determination of S.V.P by barometer tube method;
• (iv) formation of dew, mist, fog, cloud and rain;
• (v) study of dew point, humidity and relative humidity;
• (vi) hygrometry; estimation of the humidity of the atmosphere using wet and dry bulb vi. est hygrometers.

Study notes & guidance

Study Vapours using a recommended Physics textbook that follows the JAMB syllabus. Work through the contents listed above one by one, make brief notes in your own words, and then practise as many questions on this topic as you can — in Physics, understanding and steady practice matter far more than memorising. Use the objectives below as a checklist: if you can do each one confidently, you have mastered this topic.

Objectives — candidates should be able to

After studying Vapours, you should be able to:

1. Tinguish between saturated and unsaturated vapours;
2. Relate saturated vapour pressure to boiling point;
3. Determine S.V.P by barometer tube method;
4. Differentiate between dew point, humidity and relative humidity; imate the humidity of the atmosphere using wet and dry bulb hygrometers;
5. Solve numerical problems.

These objectives are from the official JAMB syllabus. Use them as a checklist — if you can do each one confidently, you have mastered this topic.

Source: official JAMB UTME Physics syllabus (IBASS, jamb.gov.ng). Reproduced for study use. Last checked: 17 Sept 2026. Always confirm the current syllabus on the official portal.