Consider two boxes containing ideal gases \( A \) and \( B \) such that their temperatures, pressures and number densities are same. The molecular size of \( A \) is half of that of \( B \) and mass of molecule \( A \) is four times that of \( B \). If the collision frequency in gas \( B \) is \( 32 \times 10^{18} / \text{s} \) then collision frequency in gas \( A \) is ________ \( / \text{s} \).
