Question

$\mathrm{\alpha }$-particles are :

• A. Negative charged particles
• B. Positive charged particles
• C. Beam of neutrons
• D. Gamma radiation

Answer 1

The correct option is B

Positive charged particles

Explanation for correct option:

Option B: Positive charged particles:

1. Alpha $\left(\mathrm{\alpha }\right)$ particles are positively charged particles consisting of two protons and two neutrons.
2. They are identical to nucleus of Helium $\mathbf{\left(}\mathbf{He}\mathbf{\right)}$ atom. Thus, alpha particles are represented as ${}_{\mathbf{2}}{}^{\mathbf{4}}\mathbf{He}$.
3. These particles played an important role in discovery of neutrons.

Explanation for incorrect options:

Option A: Negative charged particles:

1. Negatively charged particles form cathode rays.
2. When cathode rays are passed through a magnetic field, they are deflected towards negatively charged particle which shows that they consists of negatively charged particles

Option C: Beam of neutrons:

Beam of neutrons is a neutral ray consisting of stream of neutrons.

Option D: Gamma Radiation:

1. Gamma radiation is an electromagnetic radiation.
2. It is formed by decay of atoms.

Thus, Option (B) is the correct option.