A string of length \( 1 \, \text{m} \) and mass \( 2 \times 10^{-5} \, \text{kg} \) is under tension \( T \). When the string vibrates, two successive harmonics are found to occur at frequencies \( 750 \, \text{Hz} \) and \( 1000 \, \text{Hz} \). The value of tension \( T \) is _______ Newton.
