Question

Which one of the following waves/rays are used in common T.V. Remote control ?

• A. Radio waves
• B. Laser
• C. Infrared
• D. Ultrasonic

Answer 1

The Correct Option is C

To determine which type of waves or rays are used in a common T.V. remote control, let's evaluate each option given:

1. Radio Waves: These are a type of electromagnetic radiation with wavelengths that are longer than infrared light. They are commonly used for long-distance communication such as broadcasting, and mobile telephony, but not typically for T.V. remote controls.
2. Laser: While lasers are used in various applications, such as optical discs and cutting, they are not used in T.V. remote controls. Lasers could cause significant harm if directed towards eyes, making them unsuitable for common household remote controls.
3. Infrared: T.V. remote controls commonly use infrared (IR) waves. These are electromagnetic waves with longer wavelengths than those of visible light and shorter than radio waves. IR waves are invisible to the human eye but can be detected by electronic devices. This makes them ideal for remote control systems, which communicate through line-of-sight transmission.
4. Ultrasonic: These are sound waves with frequencies above the audible range for humans. While they can be used in remote controls, especially for specific industrial applications, they are not commonly used in consumer T.V. remotes.

Given the analysis above, the correct answer is Infrared, as it is widely used for operating T.V. remote controls. The remote control sends out infrared signals to the T.V. which are then interpreted into commands like volume adjustment, channel change, etc.

Conclusion: The type of waves used in common T.V. remote controls is Infrared.