The mean lives of a radioactive substance are 1620 years and 405 years for α -emission and β-emission respectively. The time during which three fourth of a sample will decay if it is decaying both by α -emission and β-emission simultaneously.
see full answer
High-Paying Jobs That Even AI Can’t Replace — Through JEE/NEET
🎯 Hear from the experts why preparing for JEE/NEET today sets you up for future-proof, high-income careers tomorrow.
An Intiative by Sri Chaitanya
a
449 years
b
349 years
c
249 years
d
149 years
answer is A.
(Unlock A.I Detailed Solution for FREE)
Best Courses for You
JEE
NEET
Foundation JEE
Foundation NEET
CBSE
Detailed Solution
Total decay constant is λ=1τ1+1τ2=11620+1405=1324sec-1 t=1λln4=324×ln4=449 yr