question_answer

If \[{{N}_{P}}\]and \[{{N}_{e}}\]be the numbers of holes and conduction electrons in an extrinsic semiconductor, then [MP PMT 1999; AMU 2001]

A)            \[{{N}_{P}}>{{N}_{e}}\]

B)            \[{{N}_{P}}={{N}_{e}}\]

C)            \[{{N}_{P}}<{{N}_{e}}\]

D)            \[{{N}_{P}}>{{N}_{e}}\] or \[{{N}_{P}}<{{N}_{e}}\] depending on the nature of impurity 

Correct Answer: D

Solution :

           \[\begin{matrix}   \text{Extrinsic} \\   \text{S}\text{.C}\text{.} \\ \end{matrix}\]  \[\begin{matrix}    P-\text{Type}\,({{n}_{p}}>>{{n}_{e}})  \\    \begin{matrix}    {}  \\    N-\text{Type}\,({{n}_{e}}>>{{n}_{p}})  \\ \end{matrix}  \\ \end{matrix}\]