Radioactive Decay

Step 1: Understand the decay formula.
The number of nuclei remaining in a radioactive sample after time is given by the equation:
where: is the initial number of nuclei, is the time elapsed, is the half-life of the substance.
Step 2: Use the given values for A and B.

For sample A, hours, For sample B, hours, After 48 hours, we calculate the remaining number of nuclei in each sample using the decay formula.
For sample A: For sample B:
Step 3: Conclusion.
After 48 hours, the ratio of to becomes: Thus, the ratio of the number of nuclei becomes 1:1.
Conclusion:
The correct answer is (A) 1:1.