A student uses a potometer to measure water uptake by a leafy shoot. With the lamp far from the shoot, the mean rate of water uptake was 0.65 mm3/min.
The student then moved the lamp closer to the shoot and carried out three trials, each lasting 4 minutes. In these trials the bubble moved 18 mm, 20 mm and 22 mm.
Water is drawn through a capillary tube with a cross-sectional area of 0.25 mm2.
Calculate the percentage increase in the mean rate of water uptake when the lamp was moved closer to the shoot. Give your answer to 3 significant figures.
80 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.