The kinetic energy of an emitted electron given is 1.986×10−19J The frequency of radiation is 1×1015s−1 The threshold frequency (vo) can be calculated as follows: hv−hvo=KE h(v−vo)=KE Substitute the values in the above formula. 6.62×10−34J.s(1×1015s−1−vo)=1.986×10−19J 1×1015s−1−v0=