The lightest particle is/are

Options

A. Electron
B. Proton
C. Neutron
D. `beta`- particle

Answer

To determine which among the given particles is the lightest, we will analyze the masses of each particle: electron, proton, neutron, and beta particle.

**Step 1: Identify the mass of each particle.**
- **Electron:** The mass of an electron is approximately \(9.1 \times 10^{-31}\) kg.
- **Proton:** The mass of a proton is approximately \(1.67 \times 10^{-27}\) kg.
- **Neutron:** The mass of a neutron is also approximately \(1.67 \times 10^{-27}\) kg, which is slightly more than that of a proton (about 0.1% heavier).
- **Beta Particle:** A beta particle is essentially an electron (or a positron in the case of beta plus decay), so its mass is also approximately \(9.1 \times 10^{-31}\) kg.

**Step 2: Compare the masses.**
- The mass of the electron is \(9.1 \times 10^{-31}\) kg.
- The mass of the proton is \(1.67 \times 10^{-27}\) kg.
- The mass of the neutron is \(1.67 \times 10^{-27}\) kg.
- The mass of the beta particle is \(9.1 \times 10^{-31}\) kg.

**Step 3: Determine the lightest particle.**
From the comparison:
- The electron and the beta particle have the same mass, which is significantly lighter than both the proton and neutron.
- The proton and neutron have similar masses, which are much heavier than that of the electron and beta particle.

**Conclusion:**
The lightest particles among the given options are the electron and the beta particle.

**Final Answer:**
The lightest particle is/are the electron and the beta particle.

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