Electromagnetic WavesHard
Question
Activity of radioactive element decreased to one third of original activity R0 in 9 years. After further 9 years, its activity will be :-
Options
A.R0
B.2/3R0
C.R0/9
D.R0/6
Solution
= e-λt ⇒ 
= e-λ(9) ...(1)∴
= e-λ(18) = [e-λ(9)]2 = 
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