Chapter 29, Problem 3RAT

The time it takes for $50\%$ of a radioactive substance to decay is known as

(a) radiometric dating.

(b) carbon-14.

(c) the proportion of atoms remaining.

(d) the half-life.

To determine

The correct option for the statement “The time it takes for $50\%$ of a radioactive substance to decay is known as”.

Answer to Problem 3RAT

The correct option for the statement “The time it takes for $50\%$ of a radioactive substance to decay is known as” is option (d).

Explanation of Solution

Every matter around us is made up of atoms, these atoms make different elements by their combination. There are some elements that have isotopes, which means same element have a different number of protons. This imbalance of neutron and proton make the element unstable, and these unstable isotopes are known as a radioactive element.

The radioactive elements have too much energy in the form of alpha, beta and gamma radiation that make them unstable. They turn into a stable state after releasing this energy. The process of releasing their energy and turning from unstable to stable elements is known as radioactive decay. The time is taking by the radioactive element to decay $50\%$ of itself is known as half-life.

Conclusion:

Therefore, the correct option for the statement “The time it takes for $50\%$ of a radioactive substance to decay is known as” is option (d).