The oscillation period \( T \) for a mass-spring system is \( T = 2 \pi \sqrt{\frac{m}{k}} \). With \( m = 0.5 \) and \( k = 200 \), the calculation is \( T = 2 \pi \sqrt{\frac{0.5}{200}} \approx 0.314 \, \text{s} \). Therefore, the oscillation period is \( 0.314 \, \text{s} \).