JEE Main 2012 Physics question
The counting rate observed from a radioactive source at t = 0 was 1600 counts , and t = 8 s, it was 100 counts . The counting rate observed as counts at t = 6 s will be
Answer: (4)
Solution
1600 → 100 is a factor of 16 = 2⁴ in 8 s, so s. At t = 6 s (3 half-lives): counts/s, option (4).