Answer:
W = 2.158 eV
fo = 5.23 x 10^14 Hz
Explanation:
f = 7.9 x 10^14 Hz, Vo = 1.1 V
Let W be the work function.
Use the Einstein equation
Energy = W + eVo
hf = W + eVo
where, h is the Plank's constant and e be the electronic charge.
W = hf - eVo
W = (6.6 x 10^-34 x 7.9 x 10^14) - (1.6 x 10^-19 x 1.1)
W = 5.214 x 10^-19 - 1.76 x 10^-19 = 3.454 x 10^-19 J
W = (3.454 x 10^-19) / (1.6 x 10^-19) = 2.158 eV
Let fo be the cut off frequency
W = h fo
fo = W / h = (3.454 x 10^-19) / (6.6 x 0^-34) = 5.23 x 10^14 Hz
