Question

Two radio waves are used in the operation of a cellular telephone. To receive a call, the phone detects the wave emitted at one frequency by the transmitter station or base unit. To send your message to the base unit, your phone emits its own wave at a different frequency. The difference between these two frequencies is fixed for all channels of cell phone operation. Suppose the wavelength of the wave emitted by the base unit is 0.34961 m and the wavelength of the wave emitted by the phone is 0.36455 m. Using a value of 2.9979 × 108 m/s for the speed of light, determine the difference between the two frequencies used in the operation of a cell phone. Give your answer to four significant figures.

Answer 1

Cellular base station transmit:

Wavelength = 0.34961 meter . . . . . Frequency = 857.505 MHz

Phone transmit:

Wavelength = 0.36455 meter . . . . . Frequency = 822.363 MHz

Difference in frequency = 35.14 MHz