Question Text
Question 1 :
Mobilities of electrons and holes in a sample of intrinsic germanium at room temperature are $0.36m^2V^{-1}s^{-1}$ and $0.17m^2V^{-1}s^{-1}$. The electron and hole densities are each equal to $2.5\times 10^{19}m^3$. The electrical conductivity of germanium is
Question 2 :
<br/>A transformer has 500 turns in its primary and 1000 turns in its secondary winding.The primary voltage is 200 V and the load in the secondary is 100 ohm.Calculate the current in the primary,assuming it to be a ideal transformer.<br/>
Question 3 :
The energy gap of silicon is $1.14\ eV$. The maximum wavelength at which silicon starts energy absorption, will be ($h = 6.62$ $\times$ <br> $ 10$ <br> $^{-34}$ <br> $Js$, $c = 3$ $\times$ $10$ <br> $^8$ <br> $ m/s$)<br/>
Question 4 :
An electron hole pair is formed when light of maximum wavelength $6000\overset {\circ}{A}$ is incident on the semiconductor. What is the band gap energy of the semiconductor?<br>$(h = 6.62\times 10^{-34} J-s)$.
Question 5 :
A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of:<br/>