The rate constant for forward reaction $\mathrm{A}\left(\mathrm{g}\right)\rightleftharpoons 2\mathrm{B}\left(\mathrm{g}\right)$ is $1.5\times {10}^{-3}{\mathrm{s}}^{-1}\text{ at }100\mathrm{K}\text{. }$If 10^-5 moles of A and 100 moles of B are present in a 10-L vessel at equilibrium, then the
rate constant for the backward reaction at this temperature is