Panel facts & stats

Question 1

Most solar cells are made from which element?

Accepted Answer

Silicon. Silicon, a semiconductor refined from sand, is the main material in most solar cells.

Question 2

In the Northern Hemisphere, which direction do fixed solar panels usually face?

Accepted Answer

South. At most Northern Hemisphere latitudes the Sun crosses the southern sky, so south-facing panels catch the most light.

Question 3

Albert Einstein's Nobel Prize in Physics was awarded for explaining which effect?

Accepted Answer

The photoelectric effect. Einstein's Nobel Prize recognized his explanation of how light knocks electrons out of materials.

Question 4

What usually happens to a solar panel's efficiency as it gets hotter?

Accepted Answer

It goes down. Solar cells lose voltage as temperature rises, so hot panels convert sunlight less efficiently.

Question 5

A solar panel collects the most energy when sunlight hits it at what angle?

Accepted Answer

Perpendicular (90°) to its surface. Light striking a panel head-on delivers the most energy per square metre.

Question 6

Which satellite, launched in 1958, was the first to be powered by solar cells?

Accepted Answer

Vanguard 1. Vanguard 1 used small solar cells to power a radio transmitter.

Question 7

What sunlight intensity is used in the standard test conditions for rating solar panels?

Accepted Answer

1,000 W/m². Panel ratings use standard test conditions of 1,000 W/m² irradiance at a 25°C cell temperature.

The basics