For a phone to pass Federal Communications Commision(FCC) certification and be sold commercially, the SAR rating should be 1.6 to 2.0W/kg or less.

Specific Absorption Rate(SAR) is a measure of rate at which RF energy is absorbed by body. It is expressed in Watt/kg. All cell phns hv SAR rating.

Electromagnetic waves cannot exist inside the bulk of conductors. And hence u cannot stay connected on ur mobile phone when in an elevator.

Microwave oven in ur kitchen has a magnetron that generates microwaves of frequency 2.45Ghz. It falls under ISM band.

Five bars in signal strength indicator of cell phone represent the levels of reception at that point in space. It corresponds to a range of -51dB(best) to -141dB(poor).

Bluetooth version 1.2 gives a data rate of 1Mbps. Version 2.0 gives a data rate of 3Mbps and version 3.0 gives a datarate of 24Mbps.

Bluetooth operates in the frequency range 2402MHz to 2480MHz dividing the channel bandwidth into 79 bands of 1MHz each.

The collapsible antenna on ur car is a quarter wave monopole. By varying it's length, its resonant frequency is changed and hence u are able to tune to any freq(though in a limited band) with a single antenna.

Omnidirectional pattern isn't d 1 dat radiates equally in all planes. It is directional in atleast one plane and non-directional in another.

maxwell's equations

What we c 2day as Maxwell's eqns aren't proposed in that form by Maxwell. His highness didn't have the knowledge of vector calculus-for it hadn't been proposed by then.