Final answer:
By the 1940s, the electric guitar was firmly established in both country and jazz music, paving the way for the birth of rock 'n' roll in the 1950s. Technological advancements and the development of steel strings further shaped its distinctive sound.
Step-by-step explanation:
The electric guitar became a staple instrument in various music genres such as country and jazz by the 1940s. Its incorporation reflected the evolving soundscapes of American music, as artists sought to amplify their sound and reach wider audiences. The combination of electric instruments with gospel, blues, country, jazz, and R&B played a significant role in the creation of rock 'n' roll, which particularly resonated with teenagers in the 1950s. The development and popularity of steel guitar strings during the 1900s contributed to the bright, crisp sound that suited the dynamics of these genres. Meanwhile, the cultural and musical landscape evolved, with the jazz scene flourishing in areas like Harlem during the 1920s, and the innovations in musical technology during the 19th and 20th centuries enabling more complex and powerful musical expressions.