Question

If half-life of radium is 77 days. Its decay constant in day will be

• A. $3\times {10}^{-3}/day$
• B. $9\times {10}^{-3}/day$
• C. $1\times {10}^{-3}/day$
• D. $6\times {10}^{-3}/day$

Answer 1

Answer: (C)

Decay constant, $\lambda =\frac{0.693}{T_{1/2}}=\frac{0.693}{77}$
$=9\times {10}^{-3}/day$