Question

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Answer 1

Answer:

Explanation:

Half life of Nobelium-253 is 97 seconds . That means after every 97 seconds half of the Nobelium amount will be disintegrated .

Time taken in bringing the sample to laboratory = 291 seconds

291 second = 291 / 97 half life

n = 3

N = $N_0 (\frac{1}{2})^n$

N₀ is original mass , N is mass after n number of half life.

N = 5 mg x $(\frac{1}{2})^3$

= .625 mg

Only  0.625 mg of Nobelium-253 will be left .