1) Ultrasound frequency is..... a) 20,000 Hz b) greater than 20,000 Hz c) less than 20,000Hz d) less than 20 Hz 2) Infrasound is.... a) greater than 20,000 Hz b) less than 20 Hz c) greater than 20 Hz d) less than 20,000 Hz 3) ultrasound is used for.... a) scanning for broken bones b) pre-natal scanning c) sonar d) communication by animals e) detecting volcanic eruptions 4) Infra sound is used for a) detecting vocanic eruptions b) pre-natal scanning c) animal communication d) detecting animal movements 5) speed = a) distance/time b) time/distance c) distance x time d) distance/0.5 time 6) A pulse of ultrasound takes 4.5s to travel from a submarine to the sea bed and back. If the speed of sound in seawater is 1520m/s, how far away is the submarine from the seabed? a) 6840m b) 3420m c) 338m d) 675m 7) Tectonic plates move because of.... a) heat b) conduction c) convection d) radiation 8) Waves that travel through the Earth are.... a) seismic waves b) longitudinal but not transverse c) transvers but not longitudinal d) transverse and longitudinal 9) P waves.... a) are longitudinal b) are transverse c) travel through solids, liquids and gases d) travel slower than S waves 10) How many seismometers are needed to accurately detect the location of an earthquake? a) 1 b) 2 c) 3 d) 4 11) P waves can travel through a solid a) True b) False 12) S waves can travel through a liquid a) True b) False 13) The crust is a) solid b) liquid c) gas 14) The mantle is mainly solid a) True b) False 15) Why cant we hear ultrasound? a) freq/pitch is too high b) freq/pitch is too low c) it is within our hearing range 16) What is frequency? a) number of vibrations per second b) time taken for vibration c) distance some travels 17) wavespeed = a) frequency X wavelength b) freq/wavelength c) wavelength/freq 18) Ultrasound spreads less than ordinary sound a) True b) False 19) Particles travel fastest in a solid a) True b) False

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