Physics (Essay) Paper 2 WASSCE (PC 2ND), 2020

Question 5

 

(a)        Explain the term forbidden gap
(b)        Name the two charge carriers in semiconductors

 

Observation

 

   Majority of candidates attempted this question but performed averagely. Performance was fair.

The expected answers are:

                     (a)        Explanation of the term “forbidden gap”

The energy barrier separating the valence band from the conduction band which the valence electron must overcome to become conducting electron.                             

(b)        Names of charge carriers in semiconductors
-           holes               

    -           electrons