Introduction to Climate Change - EPS 7 - Homework 1-5

Why is the sky blue?

gas molecules scatter short wavelengths more than long wavelengths

Large optical depth τ ≫ 1 corresponds to being

optically thick

The optical depth τ for some path of light through a gas depends on

 all of these answers

Small optical depth τ ≪ 1 corresponds to being

optically thin

What do we call the layer of the Sun that emits light to space?

photosphere

What does optically thin mean?

transparent

What color are clouds as seen from space?

 white because water drops and ice scatter all wavelengths

How deep into a gas does the gas emit radiation like a solid surface?

τ = 1

What does optically thick mean?

opaque

From what optical depth into the Sun does the Sun emit light to space?

T = 1

Who is credited with postulating the existence of a greenhouse effect and thereby kicking off the field of climate science?

 Joseph Fourier

Which of the following gases is transparent to longwave radiation?

 oxygen

Which more strongly absorbs longwave radiation?

water vapor

Which of the following is not a greenhouse gas?

nitrogen

What best describes the atmospheric greenhouse effect?

 the atmosphere lets shortwave pass through but greenhouse gases readily absorb longwave

Which of the following gases is relatively opaque to longwave radiation?

carbon dioxide

Who is credited with identifying the gases responsible for the greenhouse effect?

 John Tyndall

On planet Cruftulon, the effective height of longwave emission to space is at 3 km where the temperature is 310 K. If the lapse rate in Kruftulon’s dry atmosphere is 10 K/km, what is the surface temperature?

340 K

In what year was the greenhouse effect postulated, thereby initiating the field of climate science?

 1824

On planet Zorkon, the effective height of longwave emission to space is at 9 km where the temperature is 210 K. If the lapse rate in Zorkon’s dry atmosphere is 10 K/km, what is the surface temperature?

300 K

In what decade did measurements on Mauna Loa first document rising concentrations of CO₂?

1960s

In what year did congressional testimony first raise public awareness about global warming?

1988

Who first predicted global warming and made a calculation of Earth’s climate sensitivity?

Svante Arrhenius

What is the modern best estimate of Earth’s climate sensitivity?

 3 K

Why is the amount of oxygen in the atmosphere decreasing?

oxygen is being reacted with carbon to make carbon dioxide

If Earth’s mean temperature increases from 288 K to 291 K when CO₂ is doubled from its preindustrial concentration, what mean temperature would you expect if CO₂ were quadrupled from its preindustrial concentration?

 294 K

Which causes the greater amount of additional warming?

 an increase of CO₂ from 300 to 400 ppm

What was the preindustral concentration of carbon dioxide?

 280 ppm

Who is credited with alerting scientists to global warming by documenting the rising concentrations of carbon dioxide in the atmosphere?

 Dave Keeling

What is the mean of 0, 4, and 8?

4

What is the modern estimate for the likely range of Earth’s climate sensitivity?

 1.5 to 4.5 K

Climate sensitivity is the

 change in temperature for a doubling of CO₂

Who is credited with alerting the public to global warming with his congressional testimony?

 James Hansen

The first prediction of global warming was made in what year?

1896

what is the unit for power?

watt

what is james watt’s primary contribution?

making the steam engine much more efficient

how is a joule dened in terms of other units?

W * s

If a laser delivers 30 W of power to a target over 2 seconds, how much energy does it deliver to the target?

60 J

what is the unit for energy?

joule

Who discovered that mechanical work gets converted to heat, thereby establishing the law of conservation of energy?

James Joule

If a lightbulb produces 100 J of heat and light energy while on for 10 seconds, how much electrical power does the lightbulb consume?

10 W

The human body produces about 100 W of heat energy per time. How much heat energy does the human body emit in an hour? Recall that an hour has 3600 seconds. 

360 kJ

Who is credited with starting the industrial revolution with their invention?

James Watt

How is a Watt defined in terms of other units? 

J/s

Which of the following was responsible for the industrial revolution?

all of the other answers

Which of the following is an example of radiation?

warm hands by the fireplace

When a mass exchanges energy with a faraway mass by sending photons to it, what do we call this?

radiation

Which of the following is an example of conduction?

burn hand on hot pan

When a mass exchanges energy with an adjacent mass by jiggling against it, what do we call this?

conduction

By what process does a blob of hot air move its heat from Earth’s surface up into the atmosphere?

convection

By what process does energy from the Sun get to Earth’s surface?

radiation

Why does a small piece of burning paper float up into the air?

convection

Where does conduction move energy into, out of, or within the Earth?

from the surface to the atmosphere

Where does radiation move energy into, out of, or within the Earth?

all the other answers

When energy moves from one place to another because a mass carries that energy there, what do we call this?

convection

By what process does air that is in contact with the Earth’s surface get heat?

conduction

Which of the following is an example of convection?

hot air balloon rises

Where does convection move energy into, out of, or within the Earth?

within the atmosphere

How far does a person go if they jog at 1 m/s for 1 hour?

3.6 km

What is 20 °C in Kelvin?

293 K

Would most people consider 40 °C cold or hot?

hot

What is appropriate clothing for 300 K?

shorts and a t-shirt

Which of the following is a typical temperature on Earth?

300 K

Which of the following countries uses Fahrenheit?

none of the other answers

Using the minus-thirty-and-halve approximation, what is 50 °F in Celsius?

10 C

What is special about 0 K?

nothing moves

What is appropriate clothing for 280 K?

pants and a sweater maybe a light jacket

How many Joules of heat are generated by a heater that outputs 500 W for 10 minutes?

300 kJ

Which of the following is a typical temperature of an oven?

450 K

Would most people consider 40 K cold or hot?

cold

Using the minus-thirty-and-halve approximation, what is 110 °F in Celsius?

40 C

Using the minus-thirty-and-halve approximation, what is 80 °F in Celsius?

25 C

What is appropriate clothing for 260 K?

heavy winter jacket and earmuffs

Would most people consider 40 °F cold or hot?

cold

How long does it take to drive 5 km at 20 km/hour?

0.25 hours

What is 30 °C in Kelvin?

303 K

Which of the following is a typical temperature of the Sun?

6000 K

Which of the following is a typical temperature of a blowtorch?

2000 K

What is 0 °C in Kelvin?

273 K

Which of the three has the shortest wavelength? 

ultraviolet

Using Wien's law, what is the peak wavelength of radiation emitted by an object with a temperature of 300 K? 

10 micron

Using Wien's law, what is the peak wavelength of radiation emitted by an object with a temperature of 6000 K? 

0.5 micron

What do we call the radiation emitted by the Sun? 

shortwave

What do we call the radiation emitted by a planet? 

longwave

Which is a valid definition of wavelength?

the distance from a peak to an adjacent peak

Using Wien's law, what is the peak wavelength of radiation emitted by an object with a temperature of 100 K? 

30 micron

What of the following emits photons?

all of the other answers

Which is not a type of photon?

proton

What is another name for longwave? 

infrared

Which of the following is not the same as the rest? 

thousandth of a meter

What is true about all photons?

they travel at the same speed

Which of the three has the shortest wavelength? 

blue

When talking about the wavelengths of radiation from the Sun and Earth, it is most convenient to use which unit? 

micrometer

Which of the three has the longest wavelength? 

red

What is another name for shortwave? 

sunlight

Which of the three has the longest wavelength?

infrared

If planet A is the same temperature as planet B, but has twice the area, how much more rapidly does planet A lose energy by radiation? 

2 times

If planet A is the same size as planet B, but is twice as hot, how much more rapidly does planet A lose energy by radiation? 

16 times

Which of the following radiates the most power? 

 an object with Area = 1 m² and T = 1000 K

What is the approximate power per area emitted by the inside wall of an oven when baking a cake in W/m²?

 6 x 4.5^4