Question

A radioactive substance contains 10000 nuclei and its half-life period is 20 days. The number of nuclei present at the end of 10 days is

• A. 7070
• B. 9000
• C. 8000
• D. 7500

Hint:

To calculate the remaining number of radioactive nuclei, use the decay law and the half-life of the substance.

Answer 1

The Correct Option is B

The number of nuclei remaining after time \( t \) can be found using the formula \( N_t = N_0 e^{-\lambda t} \), where \( N_0 \) is the initial number of nuclei, \( \lambda \) is the decay constant, and \( t \) is the time. Given the half-life, we can calculate the number of nuclei remaining after 10 days.

Step 2: Conclusion.
The number of nuclei remaining at the end of 10 days is 9000, corresponding to option (b).