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nicholasjgroo
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Homework Statement
A very short pulse UV laser is used to liberate a number of electrons from the negative plate in the arrangement in (i) above. The electrons drift towards the positive plate under the influence of the electric field over a time scale much longer than the laser pulse length. Suppose that after the centre of the cloud has traveled approximately 10 mm the spatial distribution of the charge is described by a Gaussian distribution with a standard deviation of 0.5 mm. Write down an expression that relates the electric field to the charge density and calculate the change in electric field across the electron cloud if 5×10^10 electrons m^-2 were emitted during the laser pulse. Over what distance does the electric field effectively change?
Homework Equations
god knows, this guys notes don't make any sense