Question

What current flows through a 2.54cm diameter rod of pure silicon that is 20cm long when 1000V is applied?

Answer 1

Answer:
`0.0039\ A`

Step-by-step explanation:

Given

Diameter of the rod
`d=2.54\ cm`

length of rod is
`l=20\ cm`

Resistivity of silicon is
`\rho=6.4* 10^2\ \Omega-m`

cross-section of the rod
`A`

`\Rightarrow A=(\pi d^2)/(4)\\\\\Rightarrow A=(3.142* 2.54^2* 10^(-4))/(4)\\\\\Rightarrow A=5.067* 10^(-4)\ m^2`

Resistance of rod is R

`\Rightarrow R=(\rho l)/(A)`

`\Rightarrow R=(640* 0.20)/(5.067* 10^(-4))\\\\\Rightarrow R=25.26* 10^4\ \Omega`

Current is given by

`\Rightarrow I=(V)/(R)\\\\\Rightarrow I=(1000)/(25.26* 10^4)\\\\\Rightarrow I=0.0039\ A`