Please answer the following question A photoelectric effect experiment is perfor
ID: 2116541 • Letter: P
Question
Please answer the following question
A photoelectric effect experiment is performed on a Pb electrode with an area of 1.25 cm2 using light with a wavelength of 240.8 nm and the same circuit discussed in class. Calculate the work function, in electron volts, of the Pb cathode. Calculate the cutoff or threshold wavelength for this electrode. On the above graph sketch, and label, a plausible current-voltage characteristic if the Pb electrode was illuminated with light of a slightly greater intensity but same wavelength. Briefly explain your reasoning. On the above graph sketch, and label, a plausible current-voltage characteristic if the Pb electrode was illuminated with light of a slightly longer wavelength. Briefly explain your reasoning. Briefly explain the historical significance of this experiment.Explanation / Answer
a)work function=1eV
b)hc/lambda=1.6*10^-19 J
=>lambda=6.626*10^-34*3*10^8/1.6*10^-19=12.4*10^-7
c)the cutoff voltage will shift towards left
d)the cutoff voltage shift towards right
e)Historically, light has sometimes been viewed as aparticle rather than a wave; Newton, for example, thought of light this way. The particle view was pretty much discredited with Young's double slit experiment, which made things look as though light had to be a wave. But in the early 20th century, some physicists--Einstein, for one--began to examine the particle view of light again. Einstein noted that careful experiments involving the photoelectric effect could show whether light consists of particles or waves.