Chapter 18, Problem 76QAP

Interpretation Introduction

Interpretation:

The concentration of radon in air which corresponds to an activity level of 20-picocurie should be calculated.

Concept introduction:

Activity is defined as the product of rate constant and number of atoms. It is also defined as the rate of decay or expresses number of atoms decays in unit time.

The mathematical expression is given by:

$\text{A = }\lambda \text{N}$

Where, A = activity, $\lambda$ = decay constant and N = number of radioactive nuclei.

Activity can be expressed in following units:

1 Bq = 1 atom/s

1 Ci = 3.700 × 10¹⁰ atoms/s

The relation between half-life and decay constant is given by:

$\lambda \text{=}\frac{\text{0}\text{.693}}{{\text{t}}_{\text{1/2}}}$

Where, $\lambda$ = decay constant and ${\text{t}}_{\text{1/2}}$ = half-life