Question

N atoms of a radioactive element emit n alpha-particles per second. The half life of the element is –

• A. $\frac{n}{N}\sec$
• B. $\frac{N}{n}\sec$
• C. $\frac{0.693N}{n}\sec$
• D. $\frac{0.693n}{N}\sec$

Answer 1

Answer: (C)

$\frac{0.693N}{n}\sec$

Answer 2

$\frac { \mathrm { dN } } { \mathrm { dt } }$= l N ̃ $\frac { \mathrm { n } } { 1 }$ = $\frac { 0.693 } { T }$ × N ̃ T =$\frac{0.693N}{n}\sec$