Problem 1: Consider the leaky capacitor shown in the ?gure above. Spec- i?cation
ID: 2145333 • Letter: P
Question
Problem 1: Consider the leaky capacitor shown in the ?gure above. Spec-
i?cations are as follows: The plate area is A =5.0 cm2; and the gap distance
is L =30 m. The density of free electrons (that are not bound, and have the
ability to move through the insulator) is n = 1 1023 particles/m3: (a) For a
current I = 1:0 mA across the imaginary boundary, what is the rate (in par-
ticles per second) at which electrons pass by? (b) What average drift velocity
(in meters/sec) do the electrons have to give rise to this 1 mA current?
Im not sure if the pictured showed up. its not really needed
Explanation / Answer
a. total no. of electrons = 1*10^23*(5*10^-4*30) =1.5*10^21 electrons
rate of flow = 1.5*10^21 particles/sec
b. drft velocity Vd = i/neA
Vd = 0.001/(1.5*10^21* 1.6*10-^19*5*10^-4)
Vd =8.33*10^-3 m/s