Electromagnetic waves are used in many technological devices. Describe two examples of how energy from electromagnetic waves is used in technologies to do work. Include at least one wave property that is important for each example.

Example 1: Telecommunication Devices (Mobile Phones, Radios, Televisions)

Electromagnetic waves are crucial in the functioning of telecommunication devices such as mobile phones, radios, and televisions. These devices use radio waves, a type of electromagnetic wave, to transmit information. The property of wavelength is particularly important in this context. Different radio stations, for instance, broadcast at different frequencies, which correspond to different wavelengths. Your radio can tune into a particular station by selecting the appropriate wavelength.

Work done: The energy from the electromagnetic waves is used to transmit information over long distances, enabling communication.

Example 2: Microwave Ovens

Microwave ovens use another type of electromagnetic wave, microwaves, to heat food. The microwaves are absorbed by water molecules in the food. This energy causes the water molecules to vibrate, which produces heat that cooks the food. The property of frequency is important here. The frequency of the microwaves is chosen to be at a resonant frequency of water molecules, which maximizes the energy absorption and thus the heating effect.

Work done: The energy from the electromagnetic waves is used to heat and cook food.