Examen
ILE Exam Hearing Aids UPDATED Exam Questions and CORRECT Answers
- Grado
- Institución
Hand Cupped Behind Ear - Ans -first Hearing Aid -increased sound by 5-8db -included horns,trumpets, speaking tubes 1892 - Ans -carbon amplifiers patent by Alexander Bell -marketed until 1930;first patent for a telephone type hearing instrument 1920 - Ans large vacuum tubes; not portable 1938...
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