1.

Assertion : All the radioactive element are ultimately converted in lead. Reason : All the elements above lead are unstable.

Answer»

If both the assertion and the REASON are true and the reason is the CORRECT explanation of the assertion.
If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion
If Assertion is true, but the reason is false.
If Assertion is false, but the reason is true.

Solution :Explanation : When they are converted into LEAD, the emission is stopped because the nucleus of lead is stable (or lead is most stable elements in radio active SERIES)


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