How many bosons may occupy a single quantum state?

• At most one
• At most two
• Unlimited sharing is allowed

How many fermions may occupy a single quantum state?

• At most one
• At most two
• As many as arrive

The fermion rule is the exclusion principle in another form.

A gas is warmed slightly from absolute zero. What changes in its Fermi-Dirac spread?

• Only the edge near the step blurs
• Every deep state empties at once
• The step moves down to zero energy

What does the Fermi-Dirac spread look like at absolute zero?

• A gentle slope across all energies
• A sharp step at the Fermi energy
• A single tall spike at zero

When is the classical Boltzmann count good enough?

• When states vastly outnumber particles
• When every state is fully packed
• When the temperature reaches absolute zero

A student applies the Boltzmann count to electrons packed shoulder to shoulder. What is wrong?

• The Boltzmann count only works for photons
• Dense packing makes sharing common, so quantum rules apply
• Packed electrons always escape the solid

Two electrons and two photons face three open states. How does the counting differ?

• The photons get fewer arrangements than the electrons
• The electrons must pick distinct seats while the photons may share
• Both pairs are counted in exactly the same way