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An N-type silicon sample of width 4xx10^(-3)m thickness and, length 6xx10^(-2)m carries a current of 4.8 mA when the voltage is applied across the length of the sample. What is the current density? If the free electron density is 10^(22)m^(-3), then find how much time it takes for the electrons to iravel the full length of the sample. |
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Answer» Solution :The CURRENT density J is given by `J=(i)/(A)=(4.8xx10^(-3))/((4xx10^(-3))(25xx10^(-5)))=(4.8xx10^(-3))/(10^(-6))` The drift velocity `v_(d)` is given by `V_(d)=(J)/(n E)=(4800)/(10^(22)xx1.6xx10^(-19))=3m//s` The time takent is given by `t=(L)/(u_(d))=(6xx10^(-2))/(3)="0.02 SEC"` |
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