What is a phonon?

• A form of electromagnetic radiation

• A real particle like an electron

• A collective oscillation of atoms

• A type of crystal lattice

What is a crystal lattice?

• A periodic three-dimensional arrangement of atoms

• A two-dimensional structure of molecules

• A single atom in space

• A random arrangement of atoms

Which type of phonon is associated with long wavelength vibrations?

• Optical phonon

• Acoustic phonon

• Magnetic phonon

• Thermal phonon

What is the main characteristic of optical phonons?

• They are generated by sound

• They have high frequencies

• Neighbor particles oscillate in antiphase

• Neighbor particles oscillate in phase

What unique property do phonons have according to a theory by physicists at Columbia University?

• Positive mass and gravity

• Negative mass and gravity

• No mass and no gravity

• Variable mass and gravity

Why do phonons not satisfy the Pauli Exclusion Principle?

• They are bosons

• They are fermions

• They have spin

• They are real particles

In what way do phonons contribute to condensed matter physics?

• They are irrelevant to thermal conductivity

• They play a major role in thermal and electrical conductivity

• They only affect magnetic properties

• They are only theoretical constructs

How do phonons affect neutron scattering models?

• They are irrelevant to scattering models

• They only affect electron scattering

• They play a fundamental role

• They have no effect

What is a key difference between photons and phonons?

• Phonons are electromagnetic waves

• Photons can be waves or particles

• Phonons are forms of energy

• Photons are modes of vibration

Which of the following is true about phonons?

• They have positive mass

• They are forms of electromagnetic radiation

• They are modes of vibration in lattice structures

• They are real particles like electrons