The correct answer of the given question above would be the last option. The important difference between the crystals that Becquerel exposed to sunlight and the crystals that he kept in the drawer is that, there <span>was no difference between the crystals because Becquerel used uranium crystals in both instances. He concluded a mineral containing uranium could produce it's image in a photographic plate both without the sunlight and with sunlight. Hope this answer helps.
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