Man can tolerate minimum light of intensity of $10^{-10} \mathrm{Wm}^{-2} \text {. }$ If the area of the eye ball is 0.4 cm² and frequency of light is $6 \times 10^{14} \mathrm{~Hz}$ then how many photons will enter into eyes per second? (Planck's constant $\left.h=6.63 \times 10^{-34} \mathrm{Js}\right)$