How is electromagnetic spectrum ( wavelength & frequency) used to make calls on our cellphones?

Cell phones use radio waves to communicate with cell towers, and these waves have wavelengths of approximately 10-1000 m, which are much too large to be ionizing. WiFi actually operates at quite precise frequencies, either 2.4 GHz or 5 GHz, which correspond to wavelengths of either 12 cm or 6 cm.

Explanation:

When the mobile phone is turned on, it emits radio waves that consist of radio frequency (RF) energy—a form of electromagnetic radiation moving at the speed of light. It works by transmitting radio wave signals to (and receiving these from) nearby base stations.

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