Answer:
1 × 10⁸ He atoms
Explanation:
Step 1: Given data
- Diameter of a helium atom (d): 1 × 10² pm
- Total distance to be covered (D): 1 cm
Step 2: Convert "d" to meters
We will use the conversion factor 1 m = 10¹² pm.
1 × 10² pm × (1 m / 10¹² pm) = 1 × 10⁻¹⁰ m
Step 3: Convert "D" to meters
We will use the conversion factor 1 m = 100 cm.
1 cm × (1 m / 100 cm) = 0.01 m
Step 4: Calculate the number of atoms of He required
We will use the following expression.
D/d = 0.01 m / 1 × 10⁻¹⁰ m = 1 × 10⁸
