Zinc has a work function of 4.3 eV What is the longest wavelength of light in na
ID: 1508816 • Letter: Z
Question
Zinc has a work function of 4.3 eV What is the longest wavelength of light in nanometers that will cause an electron to be ejected from the surface? B. If a 5 eV strikes the surface what is the max possible velocity for the emitted electron? Zinc has a work function of 4.3 eV What is the longest wavelength of light in nanometers that will cause an electron to be ejected from the surface? B. If a 5 eV strikes the surface what is the max possible velocity for the emitted electron? What is the longest wavelength of light in nanometers that will cause an electron to be ejected from the surface? B. If a 5 eV strikes the surface what is the max possible velocity for the emitted electron?Explanation / Answer
Here KE= 0 J
W= 4.3ev = 4.3*1.6*10^-19 = 6.88*10^-19 J
By photoelectric effect
hf = W + KE -----------(1)
(6.62*10^-34)f = 6.88*10^-19
f= 1.04*10^15 Hz
When hf = 5eV = 5*1.6*10^-19 = 8.0*10^-19 J
From (1)
hf = W+KE
hf= W+1/2mv^2
8.0*10^-19 = 6.88*10^-19 + 1/2*9.1*10^-31*v^2 => v= 4.96*10^5 m/s
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