Question

A drug tagged with 4399Tc (half life=6.05h) is prepared for a patient . if the original activity of the sample was 1.1x10⁴ Bq , what is it's activity after it has been on the self for 2.0h?

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Answer 1

In spite of the apparent immutability of the heavens, Chinese astronomers were aware that new stars could appear.[15] In 185 AD, they were the first to observe and write about a supernova, now known as the SN 185.[16] The brightest stellar event in recorded history was the SN 1006 supernova, which was observed in 1006 and written about by the Egyptian astronomer Ali ibn Ridwan and several Chinese astronomers.[17] The SN 1054 supernova, which gave birth to the Crab Nebula, was also observed by Chinese and Islamic astronomers.[18][19][20]