Question

Radioactivity of `108` undecayed radioactive nuclei of half life of `50` days is equal to that of `1.2 xx 108` number of undecayed nuclei of some material with half life of `60` days
Radioactivity is proportional to half-life.
A. If both, Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both, Assertion and Reason are true but Reason is not a correct explanation of the Assertion.
C. If Assertion is true but the Reason is false.
D. If both Assertion and Reason are false.

Answer 1

Correct Answer - C
Radioactivity `=-(dN)/(dt)=lambdaN=(0.693N)/T`
`=(0.693xx10^(8))/50=(0.693xx1.2xx10^(8))/60`
`implies 0.693xx2xx10^(6)`
So, assertion is true but radioactivity `prop1/T` and not T. Therefore, the reason is false.