Question

Using flat mirrors to focus the Sun’s rays at the top of a tower, as is done by the power plant shown in the figure, is only possible because

A. the mirrors are located in a parabolic bowl.
B. the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.
C. the Earth is a sphere with a very large radius of curvature.
D. the orientations of the flat mirrors are continuously and individually adjusted by computerized controls.
E. the Sun is directly overhead in Spain for several hours each day.

Answer 1

Flat mirrors can focus sunlight at the top of a tower because the Sun is so far away that its rays are nearly parallel when they reach Earth, which is crucial for concentrating those rays efficiently. So, the best answer is b, the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.

Step-by-step explanation:

Using flat mirrors to focus the Sun's rays at the top of a tower, as is done by the power plant shown in the figure, is only possible because the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.

This parallel nature of sunlight is due to the great distance between the Sun and the Earth.

At such a distance, light rays emanating from the Sun arrive at Earth nearly parallel to each other.

This characteristic is crucial for the optimal functioning of solar power plants using flat mirrors because they rely on the parallelism of sunlight to concentrate it efficiently at a single point, such as the top of a tower.

While adjustable mirrors controlled by computers (option D) do help in continuously focusing the light as the Sun moves across the sky, the fundamental principle that allows this system to work is the near-parallel nature of sunlight, so the correct answer is B.

So, the best answer is b, the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.

Answer 2

The power plant can focus the Sun's rays using flat mirrors because the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.

Step-by-step explanation:

The correct answer is B. The mirrors used in the power plant can focus the Sun's rays because the Sun is essentially infinitely far away, so its rays are parallel when they strike the mirrors.

When the Sun is very far from Earth, the light rays that reach our planet become almost parallel. This is because the angle between rays that strike opposite parts of the Earth becomes smaller as the source of light gets farther away. When the source is infinitely distant, the rays approach us along parallel lines.