When the nucleus of uranium is bombarded with neutrons, it breaks up into two of nearly equal mass. This process is called:

Nuclear Fission

• The process of splitting a nucleus is called nuclear fission.
• Uranium or plutonium isotopes are normally used as fuel in nuclear reactors because their nuclei are relatively large and easy to split.
• For fission to happen, the uranium-235 or plutonium-239 nucleus must first absorb a neutron.
• Hence, Option 3 is correct.

Nuclear Fusion

• Nuclear Fusion is defined as the combining of two lighter nuclei into a heavier one.
• Such nuclear fusion reactions are the source of energy in the Sun and other stars.
• It takes considerable energy to force the nuclei to fuse.
• The conditions needed for this process are extreme millions of degrees of temperature and millions of pascals of pressure.
• The hydrogen bomb is based on a thermonuclear fusion reaction.

Emission

• It refers to the release or discharge of substances, energy, or radiation from a source.
• Understanding emissions is crucial for topics related to pollution, sustainable development, and global environmental agreements.

Radiation

• It refers to the emission or transmission of energy in the form of waves or particles through space or a medium.
• It can occur naturally or be man-made and can have various effects depending on its type and intensity.