Chemical Kinetics Question 339
Question: A Geigger Muller counter is used to study the radioactive process. In the absence of radioactive substance A, it counts 3 disintegration per second (dps). At the start in the presence of A, it records 23 dps; and after 10 min 13 dps,
(i) What does it count after 20 min (ii) What is the half life of A-
Options:
A) 8 dps, 10 min
B) 5 dps, 10 min
C) 5 dps, 20 min
D) 5 dps, 5 min
Show Answer
Answer:
Correct Answer: A
Solution:
[a] In the absence of A, 3 dps is zero error, hence Initial count $ =23-3=20dps $ After $ 10min=13-3=10dps $ After 20 min =5 dps (recorded =5+3=8 dps) (50% fell in 10 min, $ T_{50}=10,min $ )
