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Using the result of part (a) in 58, take into account radiation from the leaf to
Chapter 14, Problem 59GP(choose chapter or problem)
Problem 59GP
Using the result of part (a) in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature of 35°C.
A leaf of area 40 cm2 and mass 4.5 × 10–4 kg directly faces the Sun on a clear day. The leaf has an emissivity of 0.85 and a specific heat of 0.80 kcal/kg · K. (a) Estimate the rate of rise of the leaf’s temperature. (b) Calculate the temperature the leaf would reach if it lost all its heat by radiation to the surroundings at 20°C. (c) In what other ways can the heat be dissipated by the leaf?
Questions & Answers
QUESTION:
Problem 59GP
Using the result of part (a) in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature of 35°C.
A leaf of area 40 cm2 and mass 4.5 × 10–4 kg directly faces the Sun on a clear day. The leaf has an emissivity of 0.85 and a specific heat of 0.80 kcal/kg · K. (a) Estimate the rate of rise of the leaf’s temperature. (b) Calculate the temperature the leaf would reach if it lost all its heat by radiation to the surroundings at 20°C. (c) In what other ways can the heat be dissipated by the leaf?
ANSWER:
Solution 59GP
Step 1 of 4
The objective here is to calculate the amount of water that must be transpired by a leaf so as to maintain a temperature of 35°C under the given conditions.