Unit 6 Problem Set (Exam 2)

The greenhouse effect refers to
a. Heat escaping into space
b. Warming caused by greenhouse gases trapping IR radiation
c. UV absorption by O₃
d. Heat generated by Earth’s core
e. Reflection of visible light

B

The Sun emits most strongly in which region?
a. Microwave
b. Visible
c. Near-IR only
d. Gamma
e. Radio

B

Earth emits radiation mainly in the
a. UV range
b. Visible range
c. Microwave range
d. Infrared (IR) range
e. X-ray range

D

The Earth’s average surface temperature without greenhouse gases would be
a. +30°C
b. 0°C
c. –18°C
d. –2°C
e. +15°C

C

The largest contributor to the natural greenhouse effect is
a. CO₂
b. CH₄
c. O₃
d. H₂O
e. SF₆

D

Greenhouse gases warm Earth by absorbing
a. UV radiation
b. X-rays
c. Visible light
d. IR radiation
e. Gamma rays

D

Which molecules do NOT absorb IR?
a. CO₂ and H₂O
b. CH₄ and N₂O
c. N₂, O₂ and Ar
d. O₃ and CFCs
e. SF₆

C

A requirement for IR absorption is that the vibration must
a. Increase electron energy
b. Break a bond
c. Be rotational only
d. Occur in UV region
e. Change the dipole moment

E

CO₂ has how many vibrational modes?
a. 2
b. 4
c. 1
d. 5
e. 8

B

The major CO₂ IR absorption peak around 15 μm corresponds to
a. Stretching
b. Symmetric stretch
c. Bending vibration
d. Electronic transition
e. Rotational shift

C

The atmospheric window refers to a wavelength region where
a. Ozone absorbs UV
b. CO₂ absorbs all IR
c. IR escapes to space efficiently
d. Only visible light escapes
e. SF₆ absorbs strongly

C

The CO₂ atmospheric window occurs between
a. 1–2 μm
b. 20–30 μm
c. 4.3 and 15 μm
d. 2–4 μm
e. 0.2–0.3 μm

C

Albedo refers to
a. Atmospheric mass
b. IR absorption
c. Fraction of sunlight reflected
d. CO₂ concentration
e. UV exposure

C

High albedo surfaces include
a. Ice and snow
b. Oceans
c. Forests
d. Soil
e. Asphalt

A

A decrease in ice cover leads to
a. Higher albedo
b. More reflection
c. Cooling
d. More absorption + more warming
e. Less evaporation

D

The greenhouse effect becomes “enhanced” when
a. CO₂ decreases
b. IR-absorbing gases increase
c. UV radiation increases
d. O₂ dissolves in oceans
e. Nitrogen increases

B

Stratospheric cooling occurs because
a. UV decreases
b. O₃ increases
c. N₂ absorbs IR
d. More IR is absorbed in the troposphere
e. Sunlight stops reaching the stratosphere

D

What is the typical atmospheric concentration of CO₂?
a. 100 ppm
b. 500 ppm
c. 280 ppm
d. 200 ppm
e. 420 ppm

E

Seasonal CO₂ variations are mainly caused by
a. Ocean acidification
b. Fires
c. Photosynthesis and plant decay
d. Volcanoes
e. UV radiation

C

The effective lifetime of CO₂ can last
a. Days
b. Weeks
c. Decades to centuries
d. Hours
e. Years

C

The largest greenhouse gas emission is for:
a. CO₂
b. CH₄
c. H₂O vapor
d. N₂
e. Ar

A

Water vapor concentration primarily depends on
a. CO₂ levels
b. Human emissions
c. Temperature
d. Ozone concentration
e. Methane levels

C

Water vapor creates a positive feedback because
a. High albedo
b. It cools the atmosphere
c. Warming → more evaporation → more warming
d. It absorbs UV
e. It removes CO₂

C

Methane lifetime in the atmosphere is about
a. 1 day
b. 1 year
c. 10 years
d. 100 years
e. 1,000 years

C

Methane is removed mainly by
a. Ozone
b. UV light
c. N₂
d. OH radicals
e. SO₂

D

Methane is how many times more effective than CO₂ over 100 years?
a. 2×
b. 10×
c. 23×
d. 100×
e. 200×

C

Nitrous oxide (N₂O) lifetime is approximately
a. 1–5 years
b. 10 years
c. 50 years
d. 120 years
e. 5,000 years

D

SF₆ has an atmospheric lifetime of about
a. 50 years
b. 100 years
c. 500 years
d. 1,000 years
e. ~3,200 years

E

SF₆ global warming potential is approximately
a. 10×
b. 100×
c. 23,900×
d. 5,000×
e. 50×

C

CFCs absorb strongly in the
a. Visible region
b. 1 μm region
c. UV-B
d. 8–13 μm region
e. Microwave region

D

Tropospheric ozone is formed from reactions involving
a. N₂ and O₂
b. Water vapor
c. Volcanoes
d. NOₓ and hydrocarbons in sunlight
e. CO₂

D

Tropospheric ozone contributes to warming because it
a. Reflects sunlight
b. Absorbs UV
c. Absorbs IR strongly at 9–10 μm
d. Makes rain acidic
e. Forms snow

C

Which of the following GHGs have typical atmospheric concentrations in the ppt range?
a. H2O
b. N2O and H2O
c. CO2, H2O, CH4
d. CFCs
e. SF6 and CFCs

D

A temporary CO₂ sink includes
a. Deep ocean
b. Biomass (plants)
c. Rock formation
d. Coral reefs
e. Soil minerals

B

A permanent CO₂ sink includes
a. Atmosphere
b. Trees
c. Surface ocean
d. Formation of calcium carbonate
e. Air pollution control devices

D

Which is TRUE about methane trends?
a. It has decreased since 1900
b. Stays constant all year
c. It has doubled since preindustrial times
d. Removed only by rain
e. Lifetime is 500 years

C

Which greenhouse gas is short-lived but highly potent?
a. CO₂
b. N₂
c. CH₄
d. SF₆
e. O₂

C

Which statement best summarizes greenhouse gas roles?
a. Only CO₂ warms Earth
b. Only water vapor matters
c. Multiple gases contribute differently depending on lifetime and IR absorption
d. Only synthetic gases warm Earth
e. Only ozone warms Earth

C