A-LevelBiologyTransport in plantsOct/Nov 2013Paper 1 Q231 Mark
A student used a potometer to measure the rate of water loss from a plant by transpiration. The internal diameter of the capillary tube and the distance moved by the bubble in 30 seconds were recorded. The results are shown in the table. [Figure 23.1] The volume of water moved = πr² x distance moved by the bubble. Which calculation correctly shows how to determine the rate of transpiration in mm³s⁻¹?
Aπ(1.8² × 40.0) / 30
Bπ(1.8² × 40.0) × 30
C30 / π(0.9² × 40.0)
Dπ(0.9² × 40.0) / 30
✓ Correct Answer
The correct answer is D: π(0.9² × 40.0) / 30
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep