How many atoms are there in 3.4moles if helium ,show the calculation

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

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.