Home speed of light
How long does a second last? Who determined the length of a meter and the weight of a Kilo? How were the units that we use to measure weight and distances determined?
If the universe is infinite and filled with shining stars, we might expect a continuously bright sky. Why then is it dark at night?
Light is the common name for electromagnetic radiation with wavelengths of 400-750 nm.
A laser beam is a ray of light with high intensity generated through the stimulated
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