P2: Physics - Waves

• What are the 2 types of waves?

  -Transverse

  -Longitudinal
• What do waves transfer?

  Energy
• How do the particles in a wave move?

  They oscillate (vibrate)
• What directions are the oscillations in a transverse wave?

  Perpendicular
• What directions are the oscillations in a longitudinal wave?

  Parallel
• How can the direction of wave be shown?

  By the movement of a slinky
• What do all waves have?

  -Frequency

  -Amplitude

  -Wavelength

  -Period
• What is frequency?

  The number of waves passing a certain point per second (Hz)
• What is amplitude?

  The maximum displacement that any particle achieves from its undisturbed position (meters m)
• What is wavelength?

  The distance from one point on a wave to the equivalent point on the next wave (meters m)
• What is period?

  Time taken for one complete oscillation in seconds
• Wave diagram:

  Label:

  A) amplitude

  B) undisturbed posiiton

  C) wavelength

  D) crest

  E) trough

  
• What does amplitude of a wave indicate?

  The amount of energy the wave is carrying, higher the amplitude the more energy
• What is the speed of a wave?

  The speed at which energy is transferred (or wave moves)
• What are the wave length and speed?

  Proportional
• What can waves be when they reach a boundary between one medium and another?

  Reflected

  Refracted

  Absorbed

  Transmitted
• What can show what happens during reflection?

  Ray diagram
• What must you do when drawing a ray diagram?

  -Use a ruler

  -Each section of ray should have an arrow to show direction

  -Where ray meets the boundary draw a normal line

  -All needed angles should be labelled
• When waves reflect at a surface what are the angles?

  Angle of incidence and angle of reflection are equal
• Reflection ray diagram:

  Label:

  A) mirror

  B) reflected ray

  C) angle of reflection

  D) angle of incidence

  E) incident ray

  F) normal

  
• What is refraction?

  When a wave passes on from one medium to another and changes direction
• What does the direction of refraction depend on?

  -The angle which the wave hits the boundary

  -The materials involved
• In light rays, the way a material affects refraction is called?

  refractive index
• When does light bend towards the normal during refraction?

  When light travels from a material with a low refractive index to one with a higher refractive index
• When does light bend away from the normal?

  When light travels from a material with high refractive index to one with a lower refractive index
• What is refraction due to?

  The difference in the wave speed in different media
• The process of refraction:

  -The first part of the light to enter the medium slows down

  -The rest of the wave continues at high speed

  -The wave changes direction towards the normal
• Refraction ray diagram:

  Label:

  A) angel of incidence

  B) normal

  C) angle of refraction

  D) glass

  
• What does the amplitude of a sound wave relate to?

  The loudness
• What do the frequency and wavelength of a sound wave relate to?

  The pitch
• What is the range for human hearing?

  20Hz to 20kHz (20,000Hz)
• What can sound travel through?

  Solids, liquids and air
• What can sound oscillations do in a solid?

  Cause the solid to vibrate at the same frequency as the sound wave
• What does the conversion of sound waves depend on?

  The structure of the object
• What do sound waves do within the ear?

  Cause ear drums to vibrate, which we hear as noise
• What limits human hearing?

  Limited range of conversion
• Examples of sound waves being converted to vibration:

  -In ear drum

  -By microphone

  -Glass shattered by an opera singer
• What is an ultrasonic wave?

  Above 20,000Hz so they cannot be heard by humans
• What happens when an ultrasonic wave meets a boundary?

  It is partially reflected
• How can ultrasonic waves be used to figure out the distance of boundaries?

  By measuring the time taken for the reflected rays to return to a detector