A potential difference of 2V is applied between the opposite faces of a Ge crystal of area ` 1 cm^2` and thickness 0.5 mm . If the concentration of electrons in Ge is `2xx10^(19)//m^3` and mobilities of electrons and holes are `0.36(m^2)/("volt"-s) and 0.14(m^2)/("volt"-s)` respectively , then the current flowing through the plate will be

Options

A. 0.25 A
B. 0.45 A
C. 0.56 A
D. 0.64 A

Answer

D

Explanation

`sigma = "ne"=(mu_e+mu_h)=2xx10^(19)xx1.6xx10^(-19)`
`(0.36+0.14)`
`=1.6(Omega -m)^(-1)`
`R=rho (l)/A=l/(sigmaA)=(0.5xx10^(-3))/(1.6xx10^(-4))=25/8Omega`
`:. i=V/R=2/(25//8)=16/25A=0.64A`.