GENERAL GEOLOGY

GEOLOGY

STRATIGRAPHY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives?
A
25 years
B
200 years
C
400 years
D
800 years
Explanation: 

Detailed explanation-1: -Hence, the correct option is (C) 333.3 years.

Detailed explanation-2: -To determine the absolute age of this mineral sample, we simply multiply y (=0.518) times the half life of the parent atom (=2.7 million years). Thus, the absolute age of sample = y * half-life = 0.518 * 2.7 million years = 1.40 million years.

Detailed explanation-3: -In this question (t½) of isotope is 100 years, which means that after 100 years half of the sample would have decayed and half would be left as it is. After 100 years ( first half life) 40 /2 = 20 g decays and 20 g remains left.

Detailed explanation-4: -The time required for half of the original population of radioactive atoms to decay is called the half-life. The relationship between the half-life, T1/2, and the decay constant is given by T1/2 = 0.693/.

There is 1 question to complete.