What are the correct answers and explanations for questions 5, 6, and 7 regarding semiconductor properties?

Here are the answers to the questions:

5. In a semiconductor junction diode, as the depletion or barrier layer is forward-biased, the layer

• B. narrows When a p-n junction diode is forward-biased, the applied voltage reduces the potential barrier, causing the depletion region to become thinner or narrow. This allows current to flow more easily.

6. For semiconductors to have negative temperature coefficient of resistance implies that

• D. their resistance decreases with temperature A negative temperature coefficient of resistance means that as the temperature of the material increases, its electrical resistance decreases. This is characteristic of semiconductors because higher temperatures provide more thermal energy, which frees more charge carriers (electrons and holes), thereby increasing their conductivity and reducing resistance.

7. The major difference between a pure semiconductor and a pure metal is that

• C. the resistance of metals increases with temperature, while for semiconductors it is the reverse For metals, resistance generally increases with temperature because increased thermal vibrations of atoms impede the flow of electrons. For semiconductors, resistance generally decreases with temperature because higher temperatures provide more energy to break covalent bonds, generating more free charge carriers (electrons and holes) and thus increasing conductivity.