Find the frequency of light which ejects electron from a metal surface fully stopped by a retarding potential of 3 V . The photoelectric effect begins in this metal at a frequency of 6 10¹⁵ ~Hz .

Step-by-step solution

According to Einstein's photoelectric equation, E=h v-w If V_s is retarding or stopping potential and v₀ is the threshold frequency, then the above equation becomes aligned e V_s & =h v-h v₀ h v & =e V_s+h v₀ v & = e V_s h +v₀ aligned Hence, e=1.6 10⁻¹⁹ C V_s=3 ~V , v₀=6 10⁻¹⁴ ~Hz Therefore, required frequency, aligned v & = 1.6 10⁻¹⁹ 3 6.63 10⁻³⁴ +6 10¹⁴ & = 4.8 6.63 10¹⁵+6 10¹⁴ & =0.723 10¹⁵+6 10¹⁴ & =7.23 10¹⁴+6 10¹⁴ & =13.23 10¹⁴ ~Hz & =1.323 10¹⁵ ~Hz aligned