Question

An element has a half-life of 30 years. If you start with 10g of this element, how many grams of this element would remain after 60 years? show work

Answer 1

After two half-lives or 60 years, 7.5 g of the element will be left.

Explanation:

Half-life:

• In simple words, Half-life can be defined as the amount of time needed for a quantity to fall to half its value as contained at the beginning of the time period.
• In this problem the half-life of the element is thirty years, then after thirty years half of the sample would have decayed and half would be left as it is.
• After thirty years (The first half-life ) 30 /2 = 15 g declines and 15 g remains disappeared.
• And after another sixty years (The two half-lives) 15 /2 = 7.5 g declines and 7.5 g remains disappeared.
• After two half-lives or 60 years, 7.5 g of the element will be left.