**Category:** Electromagnetism  
**Subtype:** Coulomb's Law  
**Problem Description:** This problem involves two identical charged spheres that repel each other due to their like charges. The goal is to find the magnitude of the electric charge on each sphere when they are in equilibrium at a certain distance apart. 

**Key Information:**
- Mass of each sphere (\(m\)): 0.2 kg
- Length of the strings (\(l\)): 0.5 m
- Distance between the spheres at equilibrium (\(a\)): 5 cm

**Objective:** Calculate the magnitude of the electric charge (\(|q|\)) on each sphere.