Question

Carbon-14 has a half-life of 5,730 years. In how many years will 120 grams of Carbon-14 decay to 15 grams?

11,460 years
17,190 years
22, 920 years
28,650 years

Answer 1

@doafan could you help :)

Answer 2

B.
You need to divide 120 by 2 three times to get to 15 grams.

120 ÷ 2 = 60 (1 time)
60 ÷ 2= 30 (2 times)
30 ÷ 2= 15 (3 times)

So the C14 (Carbon-14) decayed until only 15 grams are left.
Now, using the amount of years for the half life (5,730) multiply it by the number of times it has decayed, which is 3 times.

5730 × 3 = 17,190

Answer 3

thank you soooo much!!!

Answer 4

@livenlearn no problem!! :D