The current flowing in silicon bar is 2.02  10^-12 A.
 10^-12 A.
<u>Explanation:</u>
Length of silicon bar, l = 10 μm = 0.001 cm 
Free electron density, Ne = 104 cm^3 
Hole density, Nh = 1016 cm^3 
μn = 1200 cm^2 / V s
μр = 500 cm^2 / V s
The total current flowing in the bar is the sum of the drift current due to the hole and the electrons.
J = Je + Jh
J = n qE μn + p qE μp
where, n and p are electron and hole densities.
J = Eq (n μn + p μp)
we know that E = V / l
So, J = (V / l) q (n μn + p μp)
      J = (1.6  10^-19) / 0.001 (104
 10^-19) / 0.001 (104  1200 + 1016
 1200 + 1016  500)
 500)
      J = 1012480  10^-16 A / m^2.
 10^-16 A / m^2.
or
J = 1.01  10^-9 A / m^2
 10^-9 A / m^2
Current, I = JA
A is the area of bar, A = 20 μm = 0.002 cm
I = 1.01  10^-9
 10^-9  0.002 = 2.02
 0.002 = 2.02  10^-12
 10^-12
So, the current flowing in silicon bar is 2.02  10^-12 A.
 10^-12 A.