Chapter 12, Problem 1Q

(a)

To determine

The explanation for the optical properties of metal.

Answer to Problem 1Q

Metals are opaque to visible light.

Explanation of Solution

Metals can absorb visible light. Again, visible can be scattered by the free electron inside the metal. As a result visible light can be easily absorbed by the metals.

Hence, Metals are opaque to the visible light.

(b)

To determine

The explanation for the optical properties of semiconductor.

Answer to Problem 1Q

Semiconductors are opaque to visible light however transparent to infrared.

Explanation of Solution

For semiconductor, the valance band can absorb the visible light as it has enough energy. As a result, the electrons can move from valance band to conduction band.

On other hand, the infrared is not has enough energy to get absorb by semi-conductor. Hence,

(c)

To determine

The explanation for the optical properties of insulator.

Answer to Problem 1Q

Many insulators are transparent to visible light.

Explanation of Solution

The visible light has not has enough energy to get absorb by insulator. As a result, the electron from valance will not able to move to conduction band. Hence, the visible light can only pass through the insulator, like diamond.