Waves carry energy. Transverse waves (like light) vibrate at right angles to their direction; longitudinal waves (like sound) vibrate along it.
Wave equation
$v = f \lambda$ speed = frequency × wavelength
Waves can reflect, refract and diffract. Light is part of the electromagnetic spectrum and can travel through a vacuum.
Remember
- $v = f\lambda$.
- Light = transverse; sound = longitudinal.