A solid AB has rock salt structure. How many atoms of A and B are present in the unit cell ?

Explanation

To determine how many atoms of A and B are present in the unit cell of a solid AB with a rock salt structure, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure**:
The rock salt structure is similar to that of NaCl, where A represents cations (A⁺) and B represents anions (B⁻). In this structure, the B⁻ ions form a face-centered cubic (FCC) arrangement.

2. **Count the Atoms of B**:
...