The atomic mass of thorium 234 Th 90 is 234.04359 u, while that of protactinium 234 Pa 91 is 234.04330 u. Find the energy released when beta decay changes 234 Th 90 into 234 Pa 91. The atomic mass of thorium 234 Th 90 is 234.04359 u while that of protactinium 234 Pa 91 is 234.04330 u. Find the energy released when beta decay changes 234 Th 90 into 234 Pa 91. September 12, 2020 Category: Uncategorised (JEE Advanced Physics by BM Sharma + GMP Solutions) , Facebook Messenger WhatsApp Share this:TwitterFacebook Related