Discussion:
Q: The average output power of a GSM cellular phone is 1.0W when it is "ON". The phone can be treated as a point source of E-M waves emitting spherical waves.
(a) Calculate the intensity and peak electric field E(max) of the phone's E-M waves in your brain, which is about 5.0cm away from the phone when it is applied directly against year ear.
(b) What is the intensity and peak electric field of E-M wave inside a microwave oven, whose area of cross-section is A=0.25m x 0.30m and the average E-M wave power is 500-W.
(c) How the electric field in (a) compares with the safety regulation of EPA for microwave oven, which says that leaking of more than 5% of the E-field from the oven is harmful to the human body.