Determine the total surface area of the leaves in cm 2 and record the value. Stepâ 2 Calculate the rate of transpiration/surface area. If you are using a gas pressure sensor to collect data, you can express these rate values as kPa/min/cm 2, where kPa (kilopascal) is a unit of pressure.Record the rate.etermine the total surface area of the leaves in cm 2 and record the value. Stepâ 2 Calculate the rate of transpiration/surface area. If you are using a gas pressure sensor to collect data, you can express these rate values as kPa/min/cm 2, where kPa (kilopascal) is a unit of pressure.
That's why cellphones are much more sophisticatedâand work in a completely different way. A cellphone handset contains a radio transmitter, for sending radio signals onward from the phone, and a radio receiver, for receiving incoming signals from other phones.
The cell phone needs much less power essentially because: The receiver on top of the cell tower affords to be much more sensitive than the receiver you can cram inside a mobile phone. (this accounts for most of the difference in needed output power on both sides) It transmits on a slightly lower frequency band, thus bearing a slightly lower propagation loss. (some 2dB, you'd make do with 2/3 of the power)