PHYS6074: Overview of the atmosphere 2

What happens to the temperature in the thermosphere?

• Increases with altitude

• Decreases with altitude

• Constant with altitude

• Essentially random

What happens to the temperature in the exosphere?

• Increases with altitude

• Decreases with altitude

• Constant with altitude

• Essentially random

Why is the exospheric temperature constant with altitude?

• Thermal conductivity is very high

• Exosphere is not very tall

• Heated from both above and below

• It's the average temperature of the galaxy

What is the scale height?

• Height over which pressure reduces by 1/e

• Height of the thermosphere

• Distance a solar UV photon travels in the atmosphere

• Altitude at which a particle's weight is equal to its upthrust

What is the definition of the thermopause?

• Where scale height is equal to the mean free path

• Where the temperature starts decreasing

• Where the temperature starts increasing

• Where the temperature drops below zero

At which altitude does the force due to solar radiation pressure on an H atom balance the force due to Earth's gravity?

• Exopause

• Thermopause

• Lagrange point

• Radiopause