Waves and Thermodynamics

What is a wave?

A wave is a periodic disturbance of a medium or space caused by vibration that transmits energy away from the source.

What does the frequency of a wave measure?

The number of vibrations or cycles per second

Do waves carry matter from one place to another?

No

What happens to wavelength as frequency increases?

Wavelength decreases (if velocity remains constant).

What is the speed of light?

3.0 × 10⁸ m/s.

What are transverse waves?

Waves where particles move perpendicular (90°) to the direction of wave propagation.

What are longitudinal waves?

Waves where particles move parallel to the direction of wave propagation.

Give an example of a transverse wave.

Water waves or electromagnetic waves.

Give an example of a longitudinal wave.

Sound waves.

What are electromagnetic waves composed of?

Oscillating electric and magnetic fields at right angles to each other.

Can electromagnetic waves travel through a vacuum?

Yes.

What is the inverse square law for EM waves?

Intensity ∝ 1/d².

What type of wave is sound?

Longitudinal.

Can sound travel through a vacuum?

No.

What is the speed of sound in air?

340 m/s.

What does higher frequency in sound mean?

Higher pitch.

What does larger amplitude in sound mean?

Louder sound.

What is the wave speed formula?

v = fλ.

What is the principle of superposition?

When two waves meet

What is constructive interference?

When two waves in phase increase amplitude.

What is destructive interference?

When two waves out of phase reduce amplitude.

What is the law of reflection?

Angle of incidence = angle of reflection.

What is the principal axis in a concave mirror?

A line through the center of curvature and the mirror’s vertex.

What is the focal length?

The distance from the mirror to the focal point.

What causes refraction?

A change in wave speed when entering a medium with a different optical density.

What is Snell’s Law (basic form)?

sin(i)/sin(r) = n₂/n₁.

What happens when light enters a denser medium?

It bends toward the normal and slows down.

What is the critical angle?

The angle of incidence where the angle of refraction is 90°.

What is total internal reflection?

Occurs when incidence > critical angle

Formula for critical angle?

sin(ic) = 1/n (from dense to air or vacuum).

What is diffraction?

Bending of waves around obstacles or through small openings.

What is the Doppler effect?

Apparent change in frequency due to movement of source/observer.

Doppler formula?

f' = (v + vo) / (v - vs) × f.

What are beats?

Result of interference between two waves of similar frequency.

Formula for beats?

f_beat = |f₁ - f₂|.

What is the fundamental frequency?

The lowest harmonic with one antinode.

Formula for harmonic wavelength on a string?

λₙ = 2L/n.

What is thermal equilibrium?

No net flow of energy between objects in thermal contact.

Zeroth Law of Thermodynamics?

If A = B and B = C in thermal equilibrium

First Law of Thermodynamics?

∆U = Q - W (internal energy = heat in - work out).

What is specific heat capacity?

Ene