**Category:** Wave Physics  
**Subtype:** Standing Waves  
**Problem Description:** The problem involves determining the distance between two consecutive antinodes (or "bụng sóng") in a standing wave on a stretched string, given the wavelength \(\lambda\).  

**Key Concept:** In a standing wave, the distance between two consecutive antinodes is half the wavelength. Therefore, the correct answer is \( \lambda / 2 \).