A radioactive element has a half-life of 2 days. What percentage would remain radioactive after 6 days? b. If the original mass was 120 grams, how much would have decayed after 6 days?

The correct answer is -

A.  12.5%

B. 105 grams.

Explanation:

Half-life is the amount of time requires to decay or convert half of the atoms of the compound or element. It is denoted by the t1/.

In this question, it is given that an element has a half-life of two days which means it becomes half of the initial amount in two days.

A. So, after six days the percentage of the amount remaining that would be

= 50*1/3

(6 days = three half-life cycle) and (one-half cycle = 50% of initial value)

= 12.5% of its initial value.

B. If the original amount of the element was 120 gram then the amount of element that decayed in six days would be:

= Initial value - remain value

= 120 - (120*12.5/100)

= 120 -15 grams

= 105 grams.

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