1. A wave traveling at 375 m/s has a wavelength of 4.2 meters. What is the frequency of the wave?

The answer is orbit around nucleus

It is either a  proton or a neutron im almost positive. hope this .

Year  1936,  lehman predicted that the earths 'inner core' is solid. she observed that the seismic signals during her study were bent and did not pass through instead bouncing back. later it was confirmed that the earth's inner core was solid made up of nickel-iron and had a molten outer core.