Final answer:
The Emergency Locator Transmitter (ELT) can be activated manually or automatically. They emit signals to aid in the location of aircraft emergencies, utilizing electromagnetic waves for broadcasting.
Step-by-step explanation:
The Emergency Locator Transmitter (ELT) is used to broadcast an alert in emergencies. They can be activated manual or automatic.
ELTs are critical safety devices found in aircraft that serve the purpose of sending out signals to aid in the location of a crash or emergency situation. These devices transmit on designated frequencies and can be triggered manually by the pilot or crew in case of an emergency. Alternatively, they are often designed to activate automatically upon sensing a heavy impact or a rapid deceleration, which can occur during an aircraft accident.
ELTs utilize electromagnetic waves for communication, similar to other technology such as cell phones, which rely on microwave frequencies and ground-based towers that facilitate signal transition between cells, ensuring continuous communication while moving.