The work function for Al, K and Pt is 4.28 eV, 2.30 eV and 5.65 eV respectively. Their respectively threshold frequencies would be:
Answer & explanation
Correct answer: option 1
Work function, $\phi_0=hv_0$
Where $v_0$ = Threshold frequency
So, $\phi_0∝v_0$
Hence Pt > Al > K