**Assertion (A):** The standard unit for measuring atomic mass is the Dalton (). <br>**Reason (R):** — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

The unified atomic mass unit ($u$) or Dalton ($Da$) is the SI-accepted unit. The numerical value is approximately the reciprocal of Avogadro's number in grams ($1/N_A \text{ g} \approx 1.66 \times 10^{-24} \text{ g}$).