According to the context, Becquerel's experiment showed that a substance could constantly emit radiation even if it was not exposed to light.
It was an experiment on the fluorescence of double sulfate of uranium and potassium where Becquerel discovered that uranium spontaneously emitted radiation naturally.
He deduced from this that uranium salts emitted radiation capable of passing through black paper and other substances opaque to ordinary light and is considered the first step in discovering radioactivity.
Therefore, we can conclude that according to the context, Becquerel's experiment showed that a substance could constantly emit radiation even if it was not exposed to light.
Learn more about Becquerel's experiment here: https://brainly.com/question/2954153
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