Which one of the following is not electromagnetic in nature?

Electromagnetic radiation consists of photons traveling in wave-like patterns at the speed of light, encompassing radio waves, infrared, visible light, ultraviolet, X-rays, and gamma rays [t2][t6]. X-rays and gamma rays are high-energy electromagnetic waves often emitted during atomic or nuclear processes [c2][t4]. Infrared rays are also part of the electromagnetic spectrum, categorized as non-ionizing radiation [t4]. In contrast, cathode rays are not electromagnetic waves; they are streams of fast-moving electrons, which are particles with mass and charge [t1][t3]. While electromagnetic radiation is described as massless photons, cathode rays are classified as particulate radiation or particle beams [t4][t5]. Historically, J.J. Thomson's experiments confirmed that cathode rays consist of electrically charged particles (electrons) rather than waves [t9]. Therefore, cathode rays are corpuscular in nature, making them the only option listed that is not electromagnetic.

Sources

1. [1] https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html
2. [2] https://en.wikipedia.org/wiki/Electromagnetic_spectrum
3. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 5.9.r. Radioactive Pollution > p. 82
4. [4] https://www.sciencedirect.com/topics/immunology-and-microbiology/radiation
5. [5] https://www.sciencedirect.com/science/article/pii/0039368187900252