∵ According Einstein's photoelectric equation, ‌
1
2
mvmax2=hv−w0 .....(i) Here, w0 is work function and v is frequency of photon. According question equation, electric field representing given as, is
E=200{sin(4π×1010)‌t+sin(4π×1015)‌t}
Here, fundamental frequency of above equation will be LCM of both component frequency. Hence, the fundamental frequencies ω=4π×1015rad ∵ω=2πv or h,v=‌
4π×1015
2Ï€
=2π×1015Hz Put the value of h,v and W0 in Eq. (i)