1. Dolphins use infrasonic vibrations to locate objects and their prey.   True   False   2. The part of the inner ear shaped like a snail is called the _______.   eardrum   hammer   cochlea   Hint Half-n-half Clue   3. Ultrasonic vibrations are used in medicine for imaging internal organs of the human body.   True   False   4. A _______ note is the lowest note obtained on blowing gently across the top of a test-tube.   overtone   fundamental   harmonic   Half-n-half Clue   5. The repetition of sound which is reflected from an object is referred to as _______.   an echo   the pitch   the amplitude   Half-n-half Clue   6. The sound of thunder is heard 10 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 _______.   33.0 m   66.0 m   1650 m   3300 m   Half-n-half Clue   7. The upper limit of frequency that can be heard by the average human is about   2000 Hz   200 Hz   20000 Hz   200000 Hz   Half-n-half Clue