The IR LED sends out light with wavelengths ________ visible light.

Question

Question

This question was previously asked in

RRB ALP Electronics Mechanic 23 Jan 2019 Official Paper (Shift 3)

Answer 1

The correct option is 3

Concept:

Infrared radiation (IR), sometimes referred to simply as infrared, have wavelengths ranging from about 700 (nm) to 1 millimeter (mm).
They have wavelengths longer than those of visible light, but shorter than those of radio waves.
The frequencies of IR are higher than those of microwaves, but lower than those of visible light, ranging from about 300 GHz to 400 THz.
Infrared radiation (IR) is a type of radiant energy that's invisible to human eyes but that we can feel as heat.

Additional Information:

Sometimes infrared rays are classified as near-infrared and far-infrared.
Near-infrared rays are used in electronic applications like TV remote sensors and photography. Their applications can be similar to visible light applications since their wavelength ranges are close.
Far infrared rays are more thermal. Anything generating heat gives out far-infrared radiation. Even the human body at 37°C gives off infrared radiations of around 800 nm wavelength.