The Gap Between the Valence and Conduction Bands of a Certain

question 20

Multiple Choice

The gap between the valence and conduction bands of a certain semiconductor is 0.85eV. When this semiconductor is used to form a light emitting diode, the wavelength of the light emitted:

• A) is in a range above 1.5 *10^-6 m
• B) is in a range below 1.5 *10^-6 m
• C) is always 1.5* 10^-6 m
• D) is in a range centered on 1.5 *10^-6 m
• E) has nothing to do with the gap

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Definitions:

Gross Profit Method

An estimating technique used to calculate inventory cost, based on the gross margin and cost of goods sold.

Gross Profit Ratio

A financial metric indicating the percentage of revenue that exceeds the cost of goods sold; it is calculated by dividing gross profit by net sales.

Ending Inventory

The monetary amount of stock available for purchase at the end of an accounting term, which is the sum of the opening inventory and purchases, less the cost of goods sold.

Retail Inventory Method

An accounting procedure for estimating the final inventory balance of a retailer by using percentages of gross margins based on sales and the cost of goods sold.