Aspects of Photoelectric Effect with Different Metals and Lights
signs of photoelectric effect would be present as photoelectric effect
is commonly intrinsic for metals
independent: type of metal, type of light, light intensity, distance
between light source and metal
dependent: current magnitude
controlled: temperature, pressure
Apparatus and materials:
zinc plates, copper plates, ultraviolet light, light bulbs, power
source, ammeter, voltmeter, coulombmeter, sandpaper, wires, crocodile
clips, caesium-antimony photocathode
Method for the control of variables:
the temperature and pressure are ...view middle of the document...
The UV light from the UV lamp used was around 400 nm in wavelength.
Thus, wavelength of photoelectric threshold of the metal should be
longer than 400 nm.
However the metals used, zinc and copper, have photoelectric
thresholds of 290 nm and 270 nm respectively. Thus the photoelectric
effect did not occur during the experiment.
Conclusion and Evaluation:
The experiment displayed some aspects of photoelectrical effect, but
could be much more effective overall.
Neither UV light, nor regular white light from a light bulb, of
various intensities induced current in the circuit. This could be
explained by a fundamental error in the structure of the circuit or
inefficient energy of the light to induce a photoelectric effect.
As the structure seems sufficient for the indication of current using
photoelectric effect, improvement could be attempted to be made by 1)
using a more powerful light source, so that the wavelength of the
light would be shorter than 270 nm, for copper, or 290 nm, for zinc,
or 2) using a different metal, so the wavelength of its photoelectric
threshold would be...