Humidity & Vapour Pressure — A/L Physics

How do I practise Humidity & Vapour Pressure?

1 question with a worked solution

1. On a particular day, the dew point of the atmosphere is 15.0 °C when the ambient room temperature is 25.0 °C. The saturated vapour pressure (SVP) of water is 1.70 kPa at 15.0 °C and 3.40 kPa at 25.0 °C. What is the relative humidity (RH) of the air?
   1. A) 40.0%
   2. B) 50.0%
   3. C) 60.0%
   4. D) 75.0%
   Check my answer

   Correct answer: B) 50.0%

   Relative humidity is defined as RH = (Actual vapour pressure at room temperature / SVP at room temperature) × 100%. Since actual vapour pressure equals the SVP at the dew point: RH = (SVP at dew point / SVP at room temperature) × 100% = (1.70 kPa / 3.40 kPa) × 100% = 0.50 × 100% = 50.0%.

   Show worked solution

   Step 1: Relative Humidity = (SVP at dew point / SVP at room temp) × 100%. Step 2: RH = (1.70 kPa / 3.40 kPa) × 100% = 50.0%. Answer: 50.0%.
   Modelled on: the A/L Physics examination pattern

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Where does Humidity & Vapour Pressure fit in the syllabus?

Unit 4.7 · Year 1 · Term 2