6. High Energy and Compact Objects

Accretion — Quiz

Test your understanding of accretion with 5 practice questions.

Practice Questions

Question 1

In a geometrically thin, optically thick accretion disk, the radial temperature profile is often approximated by a power law. Which of the following expressions correctly represents this radial dependence?

Question 2

The magnetorotational instability (MRI) is considered a crucial mechanism for angular momentum transport in accretion disks. Which of the following conditions is necessary for the MRI to operate?

Question 3

Consider an accretion disk around a black hole. If the accretion rate is extremely high, approaching or exceeding the Eddington limit, what is the most likely consequence for the disk's geometry and emission properties?

Question 4

Observational signatures of accretion disks often include quasi-periodic oscillations (QPOs) in their X-ray light curves. What do these QPOs primarily probe?

Question 5

In the context of accretion disk theory, the 'alpha-disk' model introduces a parameter $\alpha$ to describe the effective viscosity. If $\alpha$ is very small, what is the expected consequence for the disk's evolution?