Question

Statement A: $\mathrm{\alpha }-$particles have a mass equal to 4 u and charge equal to 2+ units.

Statement R: $\mathrm{\alpha }-$particles are emitted by radioactive elements.

• A. If 'A' and ‘R’ are true and 'R' is the correct reason for 'A'.
• B. If 'A' and ‘R’ are true but 'R' is not the correct reason for 'A'.
• C. If 'A' is correct and 'R' is wrong.
• D. If 'A' is wrong and ‘R’ is correct.

Answer 1

The correct option is B

If 'A' and ‘R’ are true but 'R' is not the correct reason for 'A'.

• Alpha particle is a positively charged particle having 2 units of positive charge and 4 units of mass. It's actually${\mathrm{He}}^{2+}$, a helium ion.
• Alpha particles are emitted by radioactive materials like radium and polonium.
• The energy of the fast-moving alpha particles is substantial.
• They have the ability to permeate matter to some extent.
• Hence, 'A' and ‘R’ are true but 'R' is not the correct reason for 'A'.
• Hence, option B is correct.