# Astronomy college course/Why planets lose their atmospheres/Quiz

## AstroAtmosphericLoss_Study

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### AstroAtmosphericLoss_Study-v1s1

1. It is important to distinguish between molecules (collectively) in a gas and one individual molecule. This question is about an individual molecule. For a planet with a given mass, size, and density, which has the greater escape velocity?

___ a) all molecules have the same escape velocity
___ b) the heavier molecule has the greater escape velocity
___ c) all molecules move at the escape velocity
___ d) no molecules have escape velocity
___ e) the lighter molecule has the greater escape velocity

2. It is important to distinguish between molecules (collectively) in a gas and one individual molecule. This question is about a typical molecule in the gas. For a planet with a given mass, size, and density, which type of gas is more likely to escape?

___ a) atoms in a denser gas are more likely to escape
___ b) atoms in a colder gas are more likely to escape
___ c) all types of gas are equally likely to escape
___ d) atoms in a gas with more atomic mass are more likely to escape
___ e) atoms in a hotter gas is more likely to escape

3. Which type of gas is likely to have the faster particles?

___ a) a cold gas with low mass atoms
___ b) a hot gas with low mass atoms
___ c) a cold gas with high mass atoms
___ d) a hot gas with high mass atoms
___ e) all gasses on a given planet have the same speed

4. What is it about the isotopes of Argon-36 and Argon-38 that causes their relative abundance to be so unusual on Mars?

___ a) different chemical properties
___ b) different half-life
___ c) identical abundance
___ d) different speed
___ e) identical mass

5. In the formula, ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }v_{\mathrm {escape} }^{2}=G_{\mathrm {Newton} }{\frac {M_{\mathrm {planet} }m_{\mathrm {atom} }}{r_{\mathrm {planet} }}}}$, which of the following is FALSE?

___ a) the formula can be used to estimate how fast an atom must move before exiting the planet
___ b) the formula is valid for all launch angles
___ c) the particle is assumed to have been launched vertically
___ d) the formula is valid only if the particle is launched from the surface of planet of radius rplanet
___ e) vescape is independent of matom

6. What statement is FALSE about ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }\langle v_{\mathrm {atom} }^{2}\rangle _{ave}={\frac {1}{2}}k_{\mathrm {B} }T}$?

___ a) The average speed of a low mass particle is higher than the average speed of a high mass particle
___ b) This equation does not involve the size or mass of the planet.
___ c) Temperature is measured in Kelvins
___ d) Temperature is measured in Centigrades
___ e) The kinetic energy is directly proportional to temperature.

7. ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }\langle v_{\mathrm {atom} }^{2}\rangle _{ave}={\frac {1}{2}}k_{\mathrm {B} }T}$, where T is temperature on the Kelvin scale. This formula describes:

___ a) The speed of a typical atom, where m is the mass of the planet.
___ b) The the speed an atom needs to escape the planet, where m is the mass planet.
___ c) The speed an atom needs to orbit the planet, where m is the mass of the atom.
___ d) The speed an atom needs to escape the planet, where m is the mass of the atom.
___ e) The speed of a typical atom, where m is the mass of the atom.

#### Key to AstroAtmosphericLoss_Study-v1s1

1. It is important to distinguish between molecules (collectively) in a gas and one individual molecule. This question is about an individual molecule. For a planet with a given mass, size, and density, which has the greater escape velocity?

+ a) all molecules have the same escape velocity
- b) the heavier molecule has the greater escape velocity
- c) all molecules move at the escape velocity
- d) no molecules have escape velocity
- e) the lighter molecule has the greater escape velocity

2. It is important to distinguish between molecules (collectively) in a gas and one individual molecule. This question is about a typical molecule in the gas. For a planet with a given mass, size, and density, which type of gas is more likely to escape?

- a) atoms in a denser gas are more likely to escape
- b) atoms in a colder gas are more likely to escape
- c) all types of gas are equally likely to escape
- d) atoms in a gas with more atomic mass are more likely to escape
+ e) atoms in a hotter gas is more likely to escape

3. Which type of gas is likely to have the faster particles?

- a) a cold gas with low mass atoms
+ b) a hot gas with low mass atoms
- c) a cold gas with high mass atoms
- d) a hot gas with high mass atoms
- e) all gasses on a given planet have the same speed

4. What is it about the isotopes of Argon-36 and Argon-38 that causes their relative abundance to be so unusual on Mars?

- a) different chemical properties
- b) different half-life
- c) identical abundance
+ d) different speed
- e) identical mass

5. In the formula, ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }v_{\mathrm {escape} }^{2}=G_{\mathrm {Newton} }{\frac {M_{\mathrm {planet} }m_{\mathrm {atom} }}{r_{\mathrm {planet} }}}}$, which of the following is FALSE?

- a) the formula can be used to estimate how fast an atom must move before exiting the planet
+ b) the formula is valid for all launch angles
- c) the particle is assumed to have been launched vertically
- d) the formula is valid only if the particle is launched from the surface of planet of radius rplanet
- e) vescape is independent of matom

6. What statement is FALSE about ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }\langle v_{\mathrm {atom} }^{2}\rangle _{ave}={\frac {1}{2}}k_{\mathrm {B} }T}$?

- a) The average speed of a low mass particle is higher than the average speed of a high mass particle
- b) This equation does not involve the size or mass of the planet.
- c) Temperature is measured in Kelvins
+ d) Temperature is measured in Centigrades
- e) The kinetic energy is directly proportional to temperature.

7. ${\displaystyle {\frac {1}{2}}m_{\mathrm {atom} }\langle v_{\mathrm {atom} }^{2}\rangle _{ave}={\frac {1}{2}}k_{\mathrm {B} }T}$, where T is temperature on the Kelvin scale. This formula describes:

- a) The speed of a typical atom, where m is the mass of the planet.
- b) The the speed an atom needs to escape the planet, where m is the mass planet.
- c) The speed an atom needs to orbit the planet, where m is the mass of the atom.
- d) The speed an atom needs to escape the planet, where m is the mass of the atom.
+ e) The speed of a typical atom, where m is the mass of the atom.