When was the first guitar made and how has it changed ever since 1940?

The first guitar was made in 1850, and changed from acoustic to electric by the 1940.

Explanation:

Hi, the first guitar was made in 1850 by the Spanish musician and luthier  Antonio Torres Jurado.

The Spanish guitar was an acoustic guitar, later it morphed into an amplified guitar in the hands of Rickenbacker. But it had issues with feedback because of their hollow body.

In 1940 Les Paul changed the history creating the first solid-body electric guitar, that is the most common electric guitar in present time.

Feel free to ask for more if it´s necessary.

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.