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.
At 10 times the distance between the cell phone and your head, the signal strength is 100 times less, and at 100 times the distance, it would be 10,000 times less.  Keep conversations short. The less you talk on your cell phone, the less exposure to radiation you will have.Use the speaker phone function of the cell phone. For the same reason you'd use a headset, using a speaker phone is another good option. It keeps the cell phone away from your body, and you don't have to worry about using a headset.