If N0 is the original mass of the substance of half-life period t 1/2 = 5 years, then the amount of substance left over 15 years is If N0 is the original mass of the substance of half-life period t 1/2 = 5 years then the amount of substance left over 15 years is September 4, 2021 Category: Chapter 18 - Atoms and Nuclei , JEE Mains Physics 2002-2019 Solved Video Solutions , Facebook Messenger WhatsApp Share this:TwitterFacebook Related