ILE Exam Hearing Aids with 100% correct answers

Hand Cupped Behind Ear -first Hearing Aid -increased sound by 5-8db -included horns,trumpets, speaking tubes 1892 -carbon amplifiers patent by Alexander Bell -marketed until 1930;first patent for a telephone type hearing instrument 00:03 01:36 1920 large vacuum tubes; not portable 1938 miniature vacuum tube ;crystal receivers 1930 diameter reduced 1940 bone conduction receivers were introduced 1946 first telecoil introduced 1950 bodyworn HA became convenient size 1948 transistor invented 1954 eyeglasses aids introduced 1974 microphones electrets were introduced 1964 intergrated circuit(transistors, resistors, wiring...) 1952 first transistors The Most Important function of the oval window is to : transfer vibration from the ossicular chain Hair Cells a rise from the layer on top of the : organ of corti The theory of hearing that is considered the most accurate is : Place Theory, Volley Theory, Temporal Theory The Three semicircular canals are: 1)90degress angle to one another 2)superior,posterior, and lateral 3)detectors of rotational movement in any direction The average length of an uncoiled basilar membrane is 35mm