Final answer:
Infrared remote controls use light in the form of infrared rays to transmit signals, which require a direct line of sight between the emitter and the receiver. Unlike radio waves used by Bluetooth, infrared cannot penetrate solid objects, thus ensuring the controlled device only responds when the remote is pointed directly at it.
Step-by-step explanation:
Infrared remote controls use light to carry signals between the remote control and the device it controls. This light is part of the electromagnetic spectrum and falls within the infrared rays, which have lower frequencies and longer wavelengths compared to visible light waves. Infrared communication requires a direct line of sight between the remote's infrared emitter and the device's infrared detector for the signal to be received properly. Unlike radio waves, which can penetrate through obstacles, infrared signals are blocked by solid objects. While some modern remotes use Bluetooth technology, which relies on radio waves and offers the convenience of not needing a direct line of sight, traditional television remotes emit modulated infrared beams to send their signal.
The transmission of infrared signals is a process where the emitter converts an electrical signal into an infrared light signal. This signal carries encoded instructions, such as changing the channel or adjusting the volume. The receiving device's sensor detects this light and decodes it to perform the requested action. It's important to understand that infrared signals are distinct from radio waves and microwaves, which are used in a wide variety of technologies ranging from cellular communications to microwave ovens. Infrared is typically used in remote controls because it is well-suited to short-range, line-of-sight communication.