The rate constant of a reaction at and are and respectively. Calculate the value of . (activation…

The rate constant of a reaction at $500\text{ K}$ and $700\text{ K}$ are $0\cdot02\text{ sec}^{-1}$ and $0\cdot07\text{ sec}^{-1}$ respectively. Calculate the value of $E_a$. (activation energy)

A radioactive substance which emits alpha particle follows first order reaction. The half-life period of this radioactive substance is 30 hours. Calculate the fraction in percent (%) of the radioactive substance which remains after 90 hours.