The rate of a first order reaction doubles when the temperature changes from 300 K to 310 K . The activation energy of the reaction (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) is ( $R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}, \log 2=0.3$ )

The graph obtained between $\ln k$ ( $k=$ rate constant) on $y$-axis and $1 / T$ on $x$-axis is a straight line. The slope of it is $-4 \times 10^4 \mathrm{~K}$. The activation energy of the reaction (in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)$ is $\left(R=831 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$

For a reaction, the threshold energy is $75 \mathrm{~kJ} /$ mole. If the internal energy of the reactants is 20 $\mathrm{kJ} /$ mole, the activation energy (in $\mathrm{kJ} /$ mole) is