Question

Define the term background radiation?

Answer 1

Hint: Background radiation is a measurement of the amount of ionizing radiation in the atmosphere at a given location that is not caused by the intentional placement of radiation sources. “Dose or dose rate (or an observed measure similar to the dose or dose rate) due to all sources other than the one(s) defined," the International Atomic Energy Agency defines background radiation.

Complete step-by-step solution:
The natural radiation sources include: Cosmic rays, Terrestrial (Primordial) radio nuclides, Internal Radioisotopes
COSMIC RAYS:
Extraterrestrial radiation that strikes the earth's atmosphere is known as cosmic rays.
This includes both primary and secondary schools. Protons are present in primary cosmic rays.
accounts for 80% of the total. When the main cosmic rays collide with the Earth's atmosphere,
generating secondary particle showers (electrons, muons) and emissions of electromagnetic radiation.
Terrestrial (Primordial) radionuclides:
Primordial radionuclides are terrestrial radionuclides that have been present on Earth since its formation. Their physical half-lives are on par with the earth's history (4.5 billion years). The main contributors to terrestrial radiations are their decay products. External exposure, inhalation, and absorption are the key ways they contribute.
Internal Radioisotopes:
K-40 and C-14 are internal radionuclides that are found in the human body. K-40, which emits B and Y rays and decays with a half-life of $1.3\times {10}^{9}$ years, is the main contributor.

Note: High background radiation (HBR) from thorium-containing monazite sand is known in the coastal belt of Karunagappally, Kerala, India. The median outdoor radiation levels in coastal panchayats exceed 4 mGy, and they can reach 70 mGy in some places along the coast.