What is the tendency of a material to oppose the flow of charge?

How many times did thomas edison mess up the light bulb

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?

In this thread, i would like you to comment on the nature of light and how operation of telescopes. light has a duality of a particle and a wave; which one affects your life? also how does light interact with optics inside telescopic systems? answer these questions in two paragraphs. then respond the another students response.