Write 750,000 in scientific notation

What type of electromagnetic radiation has a shorter wavelength than blue light

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?

What are the first three quantum numbers for the electrons located in subshell 2s?