A law is used to describe a body of observations, and when studying radiation there are four:
Planck's Law
This law states that every object emits radiation over the entire electromagnetic spectrum. That means that you emit radiation at all wavelengths, and so does everything around you.
Wein's Law
It states that the wavelength of peak emission is inversely proportional to the temperature of the emitting object.
Stefan–Boltzmann Law
This law states that the total amount of energy per unit area emitted by an object is proportional to the 4th power of the temperature.
Kirchhoff's Law
This law states that for an object whose temperature is not changing, an object that absorbs radiation well at a particular wavelength will also emit radiation well at that wavelength.
<span>river valleys most early civilizations grew up around river valleys because of their proximity to easy transportation (for goods)and water (for bathing,irrigation,and drinking)</span>
Following World War II, the United States emerged as one of the two dominant superpowers, turning away from its traditional isolationism and toward increased international involvement. The United States became a global influence in economic, political, military, cultural, and technological affairs.
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So b and D are wrong the answer is A
