Q 01/05

By a 2002 estimate, the sunlight Earth absorbs in what span held more energy than the world used all year?

A) About one hour

B) About one day

C) About one month

D) About six months

Answer · why

A) About one hour

About one hour of sunshine carried more energy than humanity burned through in twelve months. By 2019, with demand far higher, the span had stretched ...

Q 02/05

Which US president put solar water heaters on the White House roof, only for his successor to remove them?

A) Richard Nixon

B) Jimmy Carter

C) Gerald Ford

D) Lyndon Johnson

Answer · why

B) Jimmy Carter

Jimmy Carter's panels heated water for the building until they came down under Ronald Reagan. Barack Obama had new panels fitted to the roof in 2013, ...

Q 03/05

On which kind of day does a typical solar panel convert sunlight into electricity most efficiently?

A) Hot and sunny

B) Warm and humid

C) Cold and sunny

D) Hot and hazy

Answer · why

C) Cold and sunny

Cold and sunny days suit panels best, because a solar cell loses roughly 0.45% of its efficiency for every degree Celsius it warms. Cells in full sun ...

Q 04/05

Which ancient Greek is said to have set Roman ships ablaze at Syracuse by focusing sunlight with mirrors?

A) Pythagoras

B) Euclid

C) Aristotle

D) Archimedes

Answer · why

D) Archimedes

Archimedes gets the credit only in later retellings: the three earliest accounts of the siege never mention mirrors. Whether the trick could work has ...

Q 05/05

Which NASA Mars rover fell silent in 2018 after a planet-wide dust storm starved its solar panels?

A) Opportunity

B) Spirit

C) Sojourner

D) Perseverance

Answer · why

A) Opportunity

Opportunity was built to last 90 Martian days and kept working for more than 14 years. Engineers hoped a windy season would sweep its panels clean, bu...