JAMB Physics 2003 Question 49

Question 49

Electronics

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

  1. A.metals are harder than semiconductors
  2. B.while the resistance of metals decreases with temperature, the reverse is the case for semiconductors
  3. C.the resistance of metals increases with temperature, while for semiconductors, it is the reverse
  4. D.metals have forbidden gaps while semiconductors have not.
Show the answer and explanation

Answer: C (the resistance of metals increases with temperature, while for semiconductors, it is the reverse)

Explanation

Heating a metal makes its atoms vibrate more, raising resistance; heating a semiconductor frees more charge carriers, lowering resistance.