Frequency of the de-Broglie wave of electron in Bohr’s first orbit of hydrogen atom is __________ \( \times 10^{13} \) \( \mathrm{Hz} \) (nearest integer).
[Given: \( R_H \) (Rydberg constant) \( = 2.18 \times 10^{-18} \ \mathrm{J} \), \( h \) (Plank’s constant) \( = 6.6 \times 10^{-34} \ \mathrm{J\cdot s} \).]