Question

A free neutron decays into a proton but a free proton does not decay into neutron. This is because

• A. neutron is an uncharged particle
• B. neutron has larger rest mass than proton
• C. neutron is a composite particle made of a proton and an electron
• D. proton is a charged particle

Hint:

Neutrons and protons are fundamental particles found within the atomic nucleus.

Answer 1

The Correct Option is B

Neutrons and protons are nucleons, but neutrons are not composed of a proton and an electron. Neutrons have no net electric charge, so the electric force has a weaker effect on them. 

• Free neutrons are unstable and undergo beta decay, with a mean lifetime of around 15 minutes.
• This decay is possible because the neutron's mass is slightly greater than that of a proton.
• In contrast, free protons are stable and do not decay into neutrons.
• Neutron decay involves the conversion of a neutron into a proton, an electron, and an electron antineutrino.

The correct answer is (b) a neutron has a larger rest mass than a proton.

Discover More From Chapter: Nuclei

 

Answer 2

Neutrons and protons are fundamental particles found within the atomic nucleus. While they share similarities, they differ in stability and behavior.

Neutrons and Protons

• Neutrons and protons are both nucleons, constituting the building blocks of atomic nuclei.
• Neutrons have no net electric charge, while protons carry a positive charge.

Neutrons: Unstable and Beta Decay

• Free neutrons are unstable and have a mean lifetime of around 15 minutes.
• Neutrons undergo beta decay, a radioactive decay process, in which a neutron converts into a proton, an electron, and an electron antineutrino.

Related Concepts
Nuclear Physics	Nuclear Binding Energy	Radioactive Decay Formula
Nucleon	Size of the Nucleus	Mass Energy Equivalence
Geiger Counter	Deuteron Mass	Unit of Radioactivity

Protons: Stability and Non-Decay

• Unlike neutrons, free protons are stable and do not naturally decay into neutrons.
• Protons remain intact due to their lower mass compared to neutrons, making the decay process energetically unfavorable.

Beta Decay Equation

• The beta decay of a neutron can be represented by the equation: n → p + e- + v̄e.
• In this equation, 'n' represents the neutron, 'p' represents the proton, 'e-' represents the electron, and 'v̄e' represents the electron antineutrino

Electric Charge and Forces

• Neutrons, being electrically neutral, are less affected by the electric force compared to charged particles like protons and electrons.
• Protons, having a positive charge, experience the electric force and contribute to the overall stability of atomic nuclei.

Neutrons and protons play essential roles in the structure and stability of atomic nuclei. Neutrons are unstable and undergo beta decay, converting into protons, electrons, and electron antineutrinos. In contrast, protons remain stable and do not naturally decay into neutrons.