Small wavelength used in led bcoz we commonly use led as a flashlight.

That depends on the LED in question

It depends on the precise material used to make the LED. Different colors of LED emit different wavelengths.

These are detemined by the band gap (a zone without electrons) of the solid used in LED.

Light emitting diodes or LED is used to save on electricity. LED connectors are a semiconductor device designed to produce a certain wavelength and type of light.