For a germanium crystal,the forbidden energy gap in joules is:

$A$ piece of copper and another of germanium are cooled from room temperature to $77 \ K$. The resistance of

Define the energy gap and the forbidden gap.

Read the following statements carefully:
$Y:$ The resistivity of a semiconductor decreases with an increase in temperature.
$Z:$ In a conducting solid,the rate of collision between free electrons and ions increases with an increase in temperature.
Select the correct statement from the following:

The forbidden energy gap for a germanium crystal is approximately ....... $J$.

Choose the correct statement. In semiconductors,the valence band and conduction band