Light and Sound Flashcards
What does a wave transfer?
Energy, not matter
Waves transfer energy through the vibration of particles.
In a transverse wave, how do the vibrations of the particles move?
Perpendicular to the direction of energy
Transverse waves have vibrations that oscillate at right angles to the direction the wave travels.
In a longitudinal wave, how do the vibrations of the particles move?
Parallel to the direction of energy
Longitudinal waves have vibrations that oscillate in the same direction as the wave travels.
What is the definition of wavelength?
The distance between successive crests or troughs of a wave
Wavelength is a key characteristic of waves, influencing their energy and frequency.
What is amplitude?
The height of the wave from its rest position
Amplitude is related to the energy of the wave; higher amplitude means more energy.
In a longitudinal wave, what are areas where particles are pushed together called?
Compressions
The opposite of compressions are rarefactions, where particles are spread apart.
What determines the loudness of a sound?
Amplitude
A louder sound has a higher amplitude.
What determines the pitch of a sound?
Frequency
A high-pitched sound has a higher frequency.
Give an example of a longitudinal wave.
Sound
Sound waves are a common example of longitudinal waves.
Give an example of a transverse wave.
Light
Other examples include radio waves, microwaves, infrared, UV, X-rays, gamma rays, and water waves.
What is an object that gives off light called?
Luminous
Luminous objects emit their own light.
How can we see non-luminous objects?
Because light is reflected off the object
Non-luminous objects are visible due to light reflecting off their surfaces.
When light hits an object and ‘stops,’ what is this called?
Absorption
Absorption occurs when light is taken in by a material.
When light hits an object and bounces off, what is this called?
Reflection
Reflection is the process by which light changes direction upon hitting a surface.
What is a transparent material?
A material that lets light through without scattering
Transparent materials allow clear passage of light.
What is an opaque material?
A material that does not let light pass through
Opaque materials block light completely.
What is a translucent object?
An object that scatters light as it passes through
Translucent materials allow some light to pass but scatter it.
How do the angle of incidence and angle of reflection compare?
They are equal/the same
The law of reflection states that the angle of incidence equals the angle of reflection.
What is refraction?
The change in direction of a wave when it changes speed
Refraction occurs when a wave enters a new medium at an angle.
What happens when the speed of a wave decreases as it moves into a new substance?
It will bend towards the normal line
A decrease in speed causes the wave to change direction towards the normal.
What happens when the speed of a wave increases as it moves into a new substance?
It will bend away from the normal line
An increase in speed causes the wave to change direction away from the normal.
What is total internal reflection?
When all the light is reflected within a material
Total internal reflection occurs when light hits a boundary at a steep angle.
Give two real-life applications of total internal reflection.
- Periscopes (submarines)
- Fibre-optic communications
Total internal reflection is utilized in various optical devices.
What is the iris in the eye?
The colored circle around the pupil that controls its size
The iris adjusts the diameter of the pupil to regulate light entry.
