Question

Cosmic rays are:

• A. protons
• B. $\alpha$-particles
• C. nuclei of higher element
• D. none of the above

Answer 1

Answer: (A), (B), (C)

The correct options are
A protons
B nuclei of higher element
C $\alpha$-particles

Cosmic rays are immensely high-energy radiation, mainly originating outside the Solar System. Composed primarily of high-energy protons and atomic nuclei.
Of primary cosmic rays, which originate outside of Earth's atmosphere, about 99% are the nuclei of well-known atoms, and about 1% are solitary electrons (similar to beta particles). Of the nuclei, about 90% are simple protons; 9% are alpha particles, and 1% are the nuclei of heavier elements.