Physics @ Berkeley
Physics in the News
Title: Climate Politics: What Every President Should Know
Date: 11/14/2007
Publication: Nature Reports
Extended Text:

If you want to lead the free world, you'd better know your physics. That's the lesson from a popular undergraduate class, called 'Physics for future presidents', taught by Richard A. Muller at the University of California, Berkeley. Here he sets some typical questions. An interactive version of this quiz with extended answers is online at

1) Electricity from the wall plug costs about 10 cents per kilowatt-hour (kWh). If you were to get the same electricity by buying AAA alkaline batteries at the local store, the cost of that electricity would be:

(a) 15 cents per kWh

(b) 94 cents per kWh

(c) $2.50 per kWh

(d) $1,000 per kWh

2) A gram of which of these is most toxic?

(a) Botulinum toxin

(b) Arsenic

(c) Anthrax spores

(d) Plutonium dust (inhaled)

3) The highest achieved efficiency (solar energy converted to electrical energy) of solar cells is approximately:

(a) 4%

(b) 15%

(c) 28%

(d) 41%

4) A typical high-resolution spy satellite has how long to photograph a location?

(a) 10 seconds

(b) 1 minute

(c) 12 minutes

(d) 90 minutes

5) The dose for radiation illness (50% chance of death within a month) is 300 rem, whole body. The dose to trigger on average one cancer is:

(a) 2.5 rem

(b) 25 rem

(c) 250 rem

(d) 2,500 rem

6) Compared with a gallon of gasoline, the energy supplied by a gallon of liquid hydrogen is approximately:

(a) ⅓ (that is, it has less energy per gallon)

(b) The same energy per gallon

(c) 3 times more energy per gallon

(d) 12 times more energy per gallon

7) Compared with the energy released when a pound of gasoline is burnt, the energy released when a pound of TNT is exploded is about:

(a) 2 times greater

(b) 13 times greater

(c) the same, within 40%

(d) less by a factor of 15

8) Of the deaths caused by the Hiroshima atomic bomb, the fraction attributed to cancer was:

(a) Less than 2%

(b) About 7%

(c) About 20%

(d) More than 50%

9) A critical mass of plutonium has a volume of:

(a) 3 tablespoons

(b) 1 soft-drink can

(c) 1 gallon

(d) 3 gallons

10) In one computer cycle (a billionth of a second for a slow laptop), light travels about:

(a) 1 foot (30 centimetres)

(b) 300 metres

(c) 3 kilometres

(d) 300 kilometres

11) In the past 100 years, the carbon dioxide level in Earth's atmosphere has increased by what fraction of its previous value?

(a) Less than 1%

(b) 3%

(c) 30%

(d) 112%

12) The rocket that won the X Prize in 2004 achieved an altitude of 100 kilometres. To go into orbit would require more energy. How much more?

(a) 1.414 times more

(b) 2 times more

(c) 7 times more

(d) 32 times more

13) The International Atomic Energy Agency's 2006 estimate for the number of excess cancer deaths expected worldwide from the Chernobyl nuclear accident was:

(a) Less than 1,000

(b) 4,000

(c) 24,000

(d) 1.3 million

14) The ozone layer in the atmosphere is created by:

(a) Carbon dioxide

(b) Sunlight

(c) Sulphur from fossil fuels

(d) Chlorofluorocarbon compounds (such as Freon)

15) Light in a fibre carries more information per second than electricity in a wire because:

(a) It has a higher frequency

(b) It travels faster than electricity

(c) It makes use of quantum effects

(d) It doesn't. Wires transmit higher bit rates. (That's why they are used in computers.)

16) The power in a square kilometre of sunlight is:

(a) 1 kilowatt

(b) 1 megawatt

(c) 10 megawatts

(d) 1 gigawatt

17) To be legal for consumption in the United States, the radioactivity of one litre of ethanol (drinking alcohol) must be:

(a) Less than 12 decays per minute

(b) Below the threshold of standard Geiger counters

(c) Not measurable by accelerator mass spectrometry (the most sensitive detection method)

(d) More than 4,000 decays per minute