A sample of radioactive material has 4.0 x 10^18 atoms. If its decay constant is 0.02 s^-1, how many atoms decay in 2 seconds?
Q1. A sample of radioactive material has 4.0 x 10^18 atoms. If its decay constant is 0.02 s^-1, how many atoms decay in 2 seconds?
Answer: 1.28 x 10^18
Explanation: Using N = N0 * e^(-λt), we find the remaining atoms, then subtract from initial. Most tempting wrong option 'D' assumes linear decay.