A student used a potometer to investigate the effect of light intensity on the rate of transpiration in a leafy shoot. A bright lamp was switched on after 4 minutes.
The table below shows the results of this investigation.
| Time (minutes) | Volume of water taken up (mm3\text{mm}^3mm3) - Lamp switched on after 4 minutes | Volume of water taken up (mm3\text{mm}^3mm3) - Lamp not switched on |
|---|---|---|
| 0 | 0 | 0 |
| 1 | 5 | 5 |
| 2 | 10 | 10 |
| 3 | 15 | 15 |
| 4 | 20 | 20 |
| 5 | 28 | 25 |
| 6 | 36 | 30 |
| 7 | 45 | 35 |
| 8 | 54 | 40 |
| 9 | 63 | 45 |
| 10 | 72 | 50 |
Calculate the rate of water uptake from 7 minutes to 10 minutes when the lamp was switched on.
Use the equation:
rate of water uptake=volume of water taken uptime taken \text{rate of water uptake} = \frac{\text{volume of water taken up}}{\text{time taken}} rate of water uptake=time takenvolume of water taken up
