Question

If one starts with one curie of radioactive substance (T_1/2 = 12 hrs) the activity left after a period of 1 week will be about –

• A. 1curie
• B. 120 micro curie
• C. 60 micro curie
• D. 8 mili curie

Answer 1

Answer: (C)

60 micro curie

Answer 2

t = 1 week = 7 × 24 hrs

T_1/2 = 12 hrs ; R₀ = 1 Cin = $\frac { \mathrm { t } } { \mathrm { T } _ { 1 / 2 } }$ =$\frac { 7 \times 24 } { 12 }$= 14 ;

R = $\frac { \mathrm { R } _ { 0 } } { 2 ^ { \mathrm { n } } }$ =$\frac { 1 } { 2 ^ { 14 } }$ Ci