How to Calculate Electomagnetic Radiation in iPhones?

The Apple iPhone transmits electromagnetic radiation at a frequency 850 MHz
when connecting to an AT&T cellular network. What is the wavelength of this
electromagnetic radiation in units of meters and centimeters?

I have no idea what to do since I'm only given one piece of information!

Wavelength: lambda

c = lambda*f

lambda = (3*10^8) / (850*10^6. M = 0, 35299m = 35, 29 cm

You have the frequency, and you know that it is electromagnetic radiation which travels at the speed of light.So, use the relationship:

speed of light = frequency X wavelength

Convert your frequency into Hz, and use 3.00 X 10^8 m/s for c. Your wavelength will be in meters.