Which one among the following types of radiations has the smallest wave length?

The electromagnetic spectrum is organized by wavelength, frequency, and energy. Wavelength is inversely proportional to frequency and energy. According to the standard order of the spectrum, radio waves have the longest wavelengths, followed by microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and finally gamma rays, which have the shortest wavelengths. Among the specific options provided, microwaves have the longest wavelength (centimeters to millimeters), followed by infrared (heat energy), and then visible light (approximately 400 to 700 nanometers) [1][2]. X-rays possess significantly higher energy and higher frequency than visible light, resulting in much shorter wavelengths, typically measured in billionths of a meter [2]. Therefore, X-rays have the smallest wavelength among the four given types of radiation.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 21: Horizontal Distribution of Temperature > Insolation > p. 282
2. [2] https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum2.html