Neutron: Definition, Quarks, and Charge

Introduction

• A neutron is one of the fundamental particles that make up the nucleus of an atom.
• It plays a crucial role in determining the stability and properties of atomic nuclei.

Structure of a Neutron

• A neutron is composed of three smaller particles known as quarks.
• The specific combination of quarks in a neutron is as follows:
  • Two Down Quarks: These are negatively charged quarks.
  • One Up Quark: This is a positively charged quark.

Charge of a Neutron

• Quarks possess fractional electric charges, which are quantised in units of the elementary charge (e).
• The electric charge of a neutron is determined by the charges of its constituent quarks.
• The elementary charge (e) is approximately equal to 1.602 x 10^-19 Coulombs (C).

Calculating the Charge of a Neutron

• To calculate the charge of a neutron, we can use the charges of the quarks:
  • Two Down Quarks: -1/3e each
  • One Up Quark: +2/3e
• The total charge of a neutron (Q) can be expressed as:
  • Q = (-1/3e) + (-1/3e) + (2/3e)
  • Q = (-2/3e) + (2/3e)
  • Q = 0
• Therefore, the charge of a neutron is zero, indicating that it is electrically neutral.

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Neutron: Definition, Quarks, & Charge

Significance of Neutron Charge

• Neutrons are electrically neutral, meaning they do not carry a net electric charge.
• This neutrality is crucial for stabilising atomic nuclei since it helps balance the positive charge carried by protons in the nucleus.
• Neutrons play a critical role in the process of nuclear fusion, which powers stars like the Sun, and in nuclear reactors.