An infrared wave traveling through a vacuum has a frequency of 4.2
10^14 Hz. What is the wave's wavelength?
7.5 x 10^7 m
7.5 x 10^-7 m
O 7.1x10^-7 m
O 7.1x10^7 m

half of a circle

explanation:

the arrow and the top of the circle is matching together. it is not a polygon because a polygon would always be the same shape. therefore, an half of a circle is called semicircle so you would find the radius of it.

protons in

in physics zero. in muscle fatigue could be high

earth's neighboring galaxy, the andromeda galaxy, is a distance of 2.54×107 light-years from earth. if the lifetime of a human is taken to be 70.0 years, a spaceship would need to achieve some minimum speed min to deliver a living human being to this galaxy.