The speed of sound in air is around 330 m/s. If a bat emits a single high-pitched ‘click’ of sound in a cave that is 20m wide, calculate the time taken for the echo of the sound to return to the bat. Dolphins use seawater to transmit their high-frequency ‘clicks’. If a dolphin is 20 m away from an underwater object, deduce whether it will see the object sooner or later than the bat.
Suggest how an ultrasound scan can produce an image of an object within the human body.

Select light for the type of wave, adjust the wavelength so that the light is red, and increase the amplitude of the light to the max. then, select the start button at the source location to begin producing the waves. light is a form of electromagnetic wave, containing oscillating electric and magnetic fields. the wave amplitude detector mentioned above shows how the electric field oscillates in time at the location of the probe. the amplitude of the wave at the location of the probe is equal to the maximum electric field measured. how does the amplitude of the wave depend on the distance from the source?