Electrons and Photons

(1) c = vλ

(2) E = hυ = hc/λ

(3) (i) $KE_{max} = hυ – ϕ_o $ ϕ -> photoelectric work function

(ii) $KE_{max} = e V_o$       $v_o$ -> stopping potential

i.e. hυ – ϕ = e $v_o$

Condition: if υ = $υ_o$ then $KE_{max} = 0$
Therefore, $ϕ_o = h υ_o$

(4) Threshold: υ = $υ_o$ & λ < $λ_o$

(5) $1/2 m_e v_{max}_^2 = hυ – ϕ$ = $h(υ – υ_o)$ = $hc (1/λ – 1/λ_o)$

(6) Constants:

h = 6.63 x $10^{-34}$

m = 9.1 x $10^{-31}$

c = 3 x $10^8$ m/$s^2$
e = 1.6 x $10^{-19}$

Conversions:
1 A° = $10^{-10}$m

1 ev = 1.6 x $10^{-19}$ J

Note: Energy α frequency & Current α Intensity