Question

Consider the 𝛼-decay 90𝑇ℎ 232→88𝑅𝑎 228 . In an experiment with one gram of 90𝑇ℎ 232, the average count rate (integrated over the entire volume) measured by the 𝛼-detector is 3000 counts s -1 . If the half life of 90𝑇ℎ 232 is given as 4.4 × 1017 s, then the efficiency of the 𝛼-detector is ______(rounded off to two decimal places).
Given: Avogadro’s number = 6.023 × 1023 mol−1

Answer 1

The correct answer is: 0.72 to 0.74 (approx)