A student investigates the rate of transpiration in a leafy shoot of cherry laurel, Prunus laurocerasus, using a potometer. The capillary tube of the potometer has an internal diameter of 0.5 mm0.5\text{ mm}0.5 mm. During a 35-minute period, the air bubble moves a distance of 42 mm42\text{ mm}42 mm along the capillary tube.
Calculate the rate of transpiration for this shoot in mm3 h−1\text{mm}^3\,\text{h}^{-1}mm3h−1. Give your final answer to 3 significant figures. Use the formula:
Volume of a cylinder=πr2l \text{Volume of a cylinder} = \pi r^2 l Volume of a cylinder=πr2lThe student also prepares a transverse section of the stem of P. laurocerasus and views it under a microscope. In a micrograph of this section, a xylem vessel has an imaged width of 44 mm44\text{ mm}44 mm. The magnification of the micrograph is ×160\times 160×160.
Calculate the actual width of this xylem vessel in mm\text{mm}mm. Give your answer to 2 significant figures.
