Cosmic radiation is a part of natural background exposure due to Earth's atmosphere and magnetic fields. Which statement is true?

Cosmic radiation is a part of natural background exposure due to Earth's atmosphere and magnetic fields. Which statement is true?

• A. Is present only in space
• B. Is a source of exposure only to persons who lie in the sun
• C. Is of concern only to space travelers
• D. Earth's atmosphere and magnetic fields help shield us from cosmic radiation

Answer: (D)

Cosmic radiation is a natural background radiation from space that we are always exposed to, but Earth’s atmosphere and magnetic field act as protective barriers. The atmosphere absorbs many high‑energy particles and even produces some secondary radiation when cosmic rays interact with air molecules, while the planet’s magnetic field deflects charged particles, reducing the flux that can reach the surface. Because of this shielding, the dose we receive at ground level is low, though it increases with altitude and toward the poles where the magnetic shielding is weaker. This is why the statement that Earth’s atmosphere and magnetic fields help shield us from cosmic radiation is true. It isn’t limited to space or to people exposed to sunlight, and space travelers face higher exposure precisely because they lack this protective shielding.

Cosmic radiation is a natural background radiation from space that we are always exposed to, but Earth’s atmosphere and magnetic field act as protective barriers. The atmosphere absorbs many high‑energy particles and even produces some secondary radiation when cosmic rays interact with air molecules, while the planet’s magnetic field deflects charged particles, reducing the flux that can reach the surface. Because of this shielding, the dose we receive at ground level is low, though it increases with altitude and toward the poles where the magnetic shielding is weaker. This is why the statement that Earth’s atmosphere and magnetic fields help shield us from cosmic radiation is true. It isn’t limited to space or to people exposed to sunlight, and space travelers face higher exposure precisely because they lack this protective shielding.