1. The part of the inner ear shaped like a snail is called the _______.   cochlea   eardrum   hammer   Hint Half-n-half Clue   2. The apparatus used in a ship to find out the depth of the sea underneath is called _______.   bell jar   sonar   tuning fork   Half-n-half Clue   3. An echo from the sea-bed is received 1.50 s after an ultrasonic vibration is sent from a sonar on a ship. If the speed of sound in water is 1500 m/s, then the depth of the sea is _______.   1000 m   1125 m   2250 m   4500 m   Half-n-half Clue   4. The three little bones in the middle ear are the _______, the anvil and the stirrup.   cochlea   hammer   eardrum   Half-n-half Clue   5. Echoes are caused by _______ of sound.   refraction   reflection   rarefaction   Half-n-half Clue   6. The upper limit of frequency that can be heard by the average human is about   2000 Hz   200000 Hz   200 Hz   20000 Hz   Half-n-half Clue   7. The sound of thunder is heard 8 s after the flash of lightning. If the speed of sound in air is 330 m/s, then the cloud is at a distance of _______.   41.2 m   82.5 m   1320 m   2640 m   Half-n-half Clue