Which one of the following has highest frequency ?

The electromagnetic spectrum is organized by frequency, wavelength, and energy. Radio waves have the lowest frequency and longest wavelength [3]. Microwaves occupy a higher frequency range than radio waves [1]. X-rays are high-frequency ionizing radiations with significant penetration power [3]. However, cosmic rays, which consist of high-energy particles and extremely high-frequency electromagnetic radiation originating from outer space, possess frequencies even higher than X-rays and gamma rays [3]. In the standard ordering of the spectrum from lowest to highest frequency—radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays—cosmic rays are often placed at the extreme high-frequency end due to their immense energy levels [3]. Therefore, among the given options, cosmic rays have the highest frequency, followed by X-rays, microwaves, and radio waves.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Explanation: > p. 279
2. [3] https://www.st-andrews.ac.uk/~bds2/ltsn/ljm/JAVA/SPECTRUM/details.html
3. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > z. Ionising radiations. > p. 83