A wave is a disturbance that transfers energy through a medium without displacing the medium. There are two types of waves: transverse waves, where the direction of vibration is perpendicular to the direction of travel, and longitudinal waves, where the direction of vibration is parallel. The amplitude of a wave is its maximum displacement from the mean position. Important wave properties include speed, frequency, wavelength, and the equation that describes a traveling wave using variables like amplitude, angular velocity, time, and position. Waves can be progressive, traveling in one direction, or stationary, formed by the combination of two progressive waves traveling in opposite directions. Key wave properties include reflection, refraction, diffraction, polarization, and interference.

1. PHYSICS
Waves
Short revision series

2. What is a wave?
 A wave is a disturbance which travels
through a medium nd transfers energy from
one point to another without causing any
permanent displacement of the medium
itself
Transverse: Direction is perpendiculr to the
direction of vibration of the medium eg
plucking a string
Longitudinal: Direction is same as direction of
the vibration of the medium eg sound waves.

3.  Amplitude: maximum displacement of particles
from their mean position measured in m.

4. Important relations to remember
 Wave speed v = x/t
 F = 1/T
 v = f λ

5. Equation of a travelling wave
 y = sin θ
 y = cos θ
 Angular velocity ω = θ/t  θ = ωt
 y = sin ωt
 y = cos ωt
 y = a sin (ωt – Ф) Ф is wave constant for
wave that did not start from origin.

6.  Ф = 2πx/λ *relating Ф to x
 y = a sin (ωt – 2πx/λ)
 y = a sin (2πt/T - 2πx/λ)
 y = a sin 2π (t/T – x/λ)
 y = a sin 2π/λ (λt/T – x)  a sin 2π/λ (1/T
λt– x)
 f = 1/T
 a sin 2π/λ (f λt – x)
 v = fλ
 a sin 2π/λ (vt – x)

7. Difference btw progressive waves
and stationary waves
 Progressive: All waves whether transverse or
longitudinal are progressive waves
 Stationary: When 2 progressive waves of
equal amplitude and frequency travelling in
opposite directions combine.

8. Properties of waves
Can be:
 Reflected
 Refracted
 Diffracted
 Polarized
 And exhibit interference

9. END