Question

There is no hole current in good conductors because they

• A. have large forbidden energy gap.
• B. have overlapping valence and conduction bands.
• C. are full of electrons.
• D. have no valence band.

Hint:

In a good conductor the valence and conduction bands overlap, so there is no separate valence band to leave holes in.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
Hole current needs a nearly full valence band with a gap above it. Electrons leave the valence band and create holes there.

Step 2: Conductor Band Structure
In good conductors the valence band and conduction band overlap, so there is no forbidden energy gap.

Step 3: Effect
Electrons move freely through a continuous set of states. Current is carried by electrons alone and no distinct holes form.

Step 4: Compare the options
Overlapping valence and conduction bands is option (B).

Final Answer:
Good conductors have no hole current because their valence and conduction bands overlap. \[ \boxed{\text{(B) }\text{have overlapping valence and conduction bands.}} \]