From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). the spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. what can we conclude? from laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). the spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. what can we conclude?
a. the star is getting hotter.
b. the "star" actually is a planet.
c. the star is moving away from us.
d. the star is moving toward us.
e. the star is getting colder.

Aball is thrown horizontally from a cliff at 8m/s .in what direction is the ball moving 2s later?

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light

Why is a noble gas different from other elements?