A student investigates the rate of transpiration in a leafy shoot of a mint plant, Mentha spicata, using a potometer. The capillary tube of the potometer has an internal diameter of 0.8 mm0.8\text{ mm}0.8 mm. During a 45-minute period, the air bubble moves a distance of 24 mm24\text{ mm}24 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 M. spicata and views it under a microscope. In a micrograph of this section, a vascular bundle has an imaged width of 36 mm36\text{ mm}36 mm. The magnification of the micrograph is ×80\times 80×80.
Calculate the actual width of this vascular bundle in mm\text{mm}mm. Give your answer to 2 significant figures.
