Question

Metals are usually transparent because of their lack of a bandgap. True or false

Answer 1

Metals are usually transparent because of their lack of a bandgap. – False.

Metals are usually opaque as the radiations that are incident have frequencies within range of visibility and they excite the electrons into energy states that are unoccupied above the levels of Fermi energy.

The opacity of metals becomes low when exposed to radiations of high frequency (Alpha and Gamma rays).

Answer 2

Metals are usually transparent because of their lack of a band gap.  

This statement is false.

Explanation:

• Metals are not transparent but they are opaque.  
• Metals are electro-positive and good conductors of heat and electricity.
• The band gap in metals causes them to be insulated materials and not transparent.
• The metals' surface act as a reflector when light fall on it.
• Therefore the metals are opaque and insulated due to band gap.