Two Thin Lenses with Focal Lengths S and R and Separated

question 7

Multiple Choice

Two thin lenses with focal lengths s and r and separated by a distance d have their combined focal length given by the reciprocal of . Combine the fractions in the expression above and use the reciprocal of your result to find the combined focal length.

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Definitions:

Average Total Costs

The overall expense of creating goods divided by the number of items produced.

Output

The quantity of goods or services produced by a firm, industry, or economy within a specified period.

Total Costs

The sum of all expenses a firm incurs in producing a product or offering a service, including both fixed and variable costs.

Total Variable Costs

The sum of all costs that vary with output level, including materials, labor, and other expenses that change with production volume.