ESS15 Winter 2015 Midterm 1 Practice Questions
1. About what fraction of the Sun’s radiation energy that hits the Earth is
absorbed at the surface?
a. 50%
b. 70%
c. 30%
d. 90%
2. What are the three ways to transfer heat energy from place to place?
a. Radiation, Condensation, Electromagnetic Waves.
b. Pressure gradient force, electromagnetic force, Coriolis force.
c. Convection, Radiation, Vibration.
d. Radiation, Convection, Conduction.
e. Strong nuclear force, weak nuclear force, gravity.
3. Which of the following electromagnetic waves has the shortest waves:
a. near infrared
b. X-rays
c. Ultraviolet
d. Microwaves
e. Radio waves
4. Name two important “greenhouse gases?
a. Carbon Dioxide (CO2) and Nitrogen (N2).
b. Nitrogen (N2) and Ozone (O3).
c. Carbon Dioxide (CO2) and Methane (CH4).
d. Water Vapor (H2O) and Oxygen (O2).
e. Argon (Ar) and Carbon Dioxide (CO2)
5.
“Black bodies” (select all that apply)
a. Absorb and emit all radiation they encounter, at all wavelengths.
b. Emit radiation in proportion to the third power of their temperature.
c. Are not a good approximation for solid objects.
d. When warmer, emit radiation at longer wavelengths.
e. If they were real, would look completely black.
6. What causes the greenhouse effect?
a. More solar radiation passes through the atmosphere to the Earth’s
surface through the ozone hole
b. Large cities cause the atmosphere to cool due to their high albedo
c. Thermal radiation from a planetary surface is absorbed by vibrating
bonds in atmospheric molecules, and is re-radiated in all directions
d. Thermal radiation is generated by clouds, water vapor and nitrogen in
the atmosphere due to nuclear fusion in the sun.
e. Carbon dioxide gas excites electrons that emit quantum radiation to
outer space when return to their ground energy state.
7. Visible light makes up
a. All
b. Less than 50%
c. Less than 10%
d. Over 80%
e. None of the above.
of solar radiation.
8. Scientists discover a mysterious planet with an albedo of 0.2 that is
illuminated at a rate of 600 W/m2 by solar radiation. How much solar
radiation does it absorb?
a. 600 W/m2
b. 480 W/m2
c. 48 W/m2
d. 120 W/m2
e. 1200 W/m2
9. About what fraction of the Sun’s radiation energy that hits the Earth is
absorbed at the surface?
a. 50 %
b. 30%
c. 70%
d. 90%
10. Li’l Wayne (a.k.a. Weezie) does an impressive dance on stage. Which energy
transformations best describe what has happened.
a. Solar radiation energy at Earth’s surface à Gravitational potential
energy of air à pressure gradient force à kinetic energy of Weezie.
b. Nuclear fusion energy in sun à solar radiation energy at Earth’s
surface à chemical energy in plants à chemical energy in human à
kinetic energy of Weezie.
c. Solar radiation energy at Earth’s surface à thermal IR energy from
Earth’s atmosphere à heat energy on Weezie’s skin à kinetic energy
of Weezie
d. Nuclear fusion energy in sun à thermal IR energy at Earth’s surface à
heat energy on Weezie’s skin à kinetic energy of Weezie.
11. Thermal infrared radiation is (select all that apply)
a. The main type of energy emitted by the sun
b. Absorbed and remitted by greenhouse gases in the atmosphere.
c. The type of energy that is wasted as heat in incandescent light bulbs.
d. Being emitted by everything around us in everyday life.
e. Not an important source of heat to the Earth’s surface.
12. The pressure gradient force of air (select all that apply)
a. Causes air to blow out of a punctured bicycle tire.
b. Causes the wind to blow from ocean to land during the night.
c. Is caused by moving molecules bouncing into each other and
shouldering each other out of the way.
d. Can be thought of as latent heat energy
13. Which of the following surface types has the highest albedo?
a) Grasslands
b) Snow
c) Asphalt
d) Desert
e) Ocean
14. If there were no greenhouse gases in the Earth’s atmosphere (select all that
apply)
a. Less solar radiation would reach the planet
b. The oceans would be frozen solid
c. Nitrogen would disappear from the atmosphere
d. Life would never have evolved.
15. Put the following section of the electromagnetic spectrum in order of shortest
to longest wavelength:
a. near infrared, Ultraviolet, X-rays, microwaves.
b. X-rays, Ultraviolet, near infrared, microwaves.
c. microwaves, near infrared, Ultraviolet, X-rays.
16. Latent heat of water (select all that apply)
a. Is released to air when cloud droplets form, heating the atmosphere
b. Is absorbed when cloud droplets form, cooling the atmosphere
c. Is absorbed in air when seawater is evaporated, cooling the ocean
d. Is released when seawater is evaporated, heating the ocean
e. Does not play a major role in warming a cold canned beverage in warm,
humid places.
17. Carbon dioxide molecules (select all that apply)
a. Are one of the most abundant constituents of the atmosphere.
b. Can dance in many ways, thus absorbing and emitting many thermal
infrared photons of many wavelengths
c. Can dance in many ways, thus absorbing and emitting certain important
wavelengths of visible radiation.
d. Protect the Earth’s surface from harmful ultraviolet radiation
e. Are the most significant gas producing the natural greenhouse effect.
18. Which statement best describes the greenhouse effect?
a. Ultraviolet light from the sun is absorbed and re-emitted by certain
greenhouse gases but the atmosphere transmits outgoing visible
radiation from the Earth
b. Infrared radiation is emitted from the sun and is absorbed and reemitted by the greenhouse gases.
c. Visible light from the sun is absorbed by greenhouse gases but
infrared radiation from the Earth is transmitted
d. Visible light from the sun is transmitted by the atmosphere, but
greenhouse gases absorb and re-emitted outgoing infrared radiation
from the Earth.
19. Which of the following processes is most responsible for removing energy
from the Earth surface, in order of biggest to smallest energy removal
a. Convection, longwave, evaporation
b. Longwave emission, evaporation, convection
c. Evaporation, convection, longwave emission
d. Longwave emission, convection, evaporation
e. Evaporation, convection, longwave emission
20. The Earth’s surface receives absorbs about
as much
energy from downward thermal infrared radiation as it absorbs from solar
radiation.
a. One tenth
b. Half
c. Twice
d. Four times
e. Ten times
21. Which of the following energy transformations best describes how hurricanes
happen? (select one)
a. Solar radiation is converted to latent heat energy of water vapor
through seawater evaporation.
b. Heating of air is converted to kinetic energy of air (winds) through
pressure gradient forces & the wind rotates because of Coriolis forces.
c. Nuclear energy of fusion in sun is converted to solar radiation.
d. Cloud formation (condensation) converts latent energy of water vapor
to heating of air.
e. All of the above.
Part B. Short answer questions (2 questions, 10 pts total)
Q1. (4 pts) Carbon pollution is often measured in “gigatons”. But how much stuff
is a “gigaton”? One way to think about it is to imagine a giant cube of liquid water.
How long on each edge would this cube have to be to weigh one “gigaton”?
Important Formulas and Values (everything you need to succeed!):
Density of water = 1000 kg/m3
Volume of a cube (in m3) = (edge length in meters) 3
One gigaton = 1 billion metric tons = 1 000 000 000 000 kg = 1012 kg
mass (kg) = density (kg/m3) x volume (m3)
a) Starting with the mass of a gigaton in kg, calculate the volume (in m3) that
a 1-gigaton cube of water would have to occupy.
Volume = mass/density = 1012 kg / 103 kg/m3 = 109 m3
b) Based on your answer, and using the equation for the volume of a cube,
calculate the edge length in meters of a one gigaton cube of water.
Edge length = (109 m3)1/3 = 1000 m.
(To put this in perspective, the diameter of the inner ring road of Aldrich Park
is about 250 m).
Q2. (6 pts) The sun powers the climate of the Earth and all the planets. We
know it must be really bright because even way out here at Earth’s orbit we
still get over 1000 W or energy per square meter coming in from it! But how
much energy comes out of the sun, total? In other words, if the sun were a
lightbulb, how many Watts would it take to power it and therefore the whole
solar system?
Important Formulas and Values (everything you need to succeed!):
F (W/m2) = σ T4
(Stefan-Boltzmann Law)
σ = 5.67 x 10-8 W/m2/K4
Area of a sphere (in m2) = 4πr2
Radius of the sun, r = 7 x 108 m
Temperature of the sun = 6000 K
a. (3) Calculate the energy flux that glows from the surface of the sun in units
of W/m2. Assume the sun is a blackbody.
b. (3) Calculate the surface area of the sun (in m2) assuming it is a sphere.
c. (3) Use your answers in a) and b) to calculate the energy in Watts that the
sun emits. Hint: It should be a REALLY big number!