Question

Choose the correct statement. In semiconductors, the valence band and conduction band are

• A. separated by a large energy gap
• B. separated by a small energy gap
• C. almost empty
• D. overlapping each other

Hint:

To remember this classification easily, associate the band gaps with electrical behavior: Overlapping means electrons move completely freely (Conductors), a Large gap acts as an impassable wall (Insulators), and a Small gap allows partial or temperature-dependent electron passage (Semiconductors).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
Identify the correct energy band gap feature characterizing a semiconductor material.

Step 2: Key Formula or Approach:
Semiconductors have a small forbidden energy gap (E_g<3 eV) between the filled valence band and the empty conduction band.

Step 3: Detailed Explanation:
Unlike insulators (large gap) or conductors (overlapping bands), semiconductors possess a small gap that allows thermal excitation of electrons at room temperature.

Step 4: Final Answer:
Bands are separated by a small energy gap, matching option (B).