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neurologyYou need to know

• A point source in a uniform medium produces circular wavefronts in two dimensions or spherical wavefronts in three dimensions.
• A wavefront is a line or surface joining points on a wave that are in the same phase.
• Transverse motion is when the oscillations are perpendicular to the direction of energy transfer.
• Diffraction is the spreading out of waves when they pass through a gap or around an obstacle, and its effects are more pronounced when the gap is similar in size to the wavelength.
• Sound is produced when objects vibrate.
• Faster vibrations (higher frequency) produce higher pitch sounds; larger vibrations (greater amplitude) produce louder sounds.
• Wavelength is the distance between two consecutive points in phase on a wave, such as from crest to crest.
• Frequency is the number of complete waves passing a point per second and is measured in hertz (Hz).
• Amplitude is the maximum displacement from the rest position.
• The frequency of a sound wave determines its pitch; the amplitude determines its volume (loudness).
• Sound is transmitted as a longitudinal wave, consisting of compressions and rarefactions.
• Sound cannot be transmitted through a vacuum because there are no particles to carry the vibrations.
• Reflection is when a wave bounces off a surface; transmission is when a wave passes through a material; absorption is when a wave's energy is taken in by a material.
• Echoes are produced when sound waves reflect off surfaces and return to the listener.
• The outer ear collects sound, the ear canal directs sound waves to the eardrum, the eardrum vibrates, the ossicles transmit and amplify the vibrations, the cochlea converts them into electrical impulses, and the auditory nerve carries the impulses to the brain.
• Sensitive microphones can detect sounds much quieter than the human ear.
• Humans have an auditory range of approximately 20 Hz to 20,000 Hz.
• Different animals have different auditory ranges, often extending beyond the human range.
• Various factors, such as age, exposure to loud sounds, and genetics, can affect the auditory range of humans.
• Sound travels as a pressure wave, transferring energy from the source to the surroundings.
• Pressure waves consist of alternating regions of high and low pressure.
• Sound waves can be used in a range of applications, such as sonar, medical imaging (ultrasound), and communication.
• The horizontal axis of an oscilloscope trace represents time, so wavelength cannot be read directly from the trace.

• Describe, with examples, the processes and effects of diffraction on waves.
• Describe how a loudspeaker works, including how electrical signals cause a diaphragm to vibrate and produce sound.
• Explain how different musical instruments produce their sounds, such as strings, wind, and percussion instruments.
• Determine the amplitude from the vertical scale and the period from the horizontal time-base of an oscilloscope trace, and calculate frequency using `f = \frac{1}{T}`, where `f` is frequency and `T` is period.
• Describe how sound is transmitted through different media, including solids, liquids, and gases.
• Describe the features of sound as a longitudinal wave, including compressions and rarefactions.
• Describe how echoes are produced and predict whether different materials will produce an echo based on their properties.
• Compare the function of parts of the ear to parts of a microphone.
• Compare the auditory range of humans to those of different animals.
• Describe pressure waves as alternating regions of high and low pressure which transfer energy from a source.
• Describe different uses of pressure waves, such as in sonar or ultrasound imaging.