Chapter 21, Problem 21.37QP

Interpretation Introduction

Interpretation: The time taken by the given isotope to decay to the given mass percentage from the given half life is to be calculated.

Concept introduction: The time taken for decay is calculated by the formula,

$\text{Time}=-\frac{\text{Half}\text{life}}{0.693}\times \ln \frac{\text{Final}\text{amount}}{\text{Initial}\text{amount}}$

To determine: The time taken by $\text{cesium}-137$ to decay to $5\%$.