Chapter 9, Problem 24P

Interpretation Introduction

(a)

Interpretation:

To analyse whether the given statement - Half-life is the time it takes one-half of a radioactive sample to decay, is true or not.

Concept Introduction:

Half-life is defined as a time required for decaying one-half part of any sample which is a radioactive material. Some elements are having isotopes that decay and disappear in a day while some can remain radioactive for billions of years. It can be calculated as below:

${\left(\frac{1}{2}\right)}^{\text{X}}$ where x is the number of half-life and the value comes as sample remains after decay.

Interpretation Introduction

(b)

Interpretation:

To analyse whether the given statement − The concept of half-life refers to nuclei undergoing alpha, beta, and positron emission; it does not apply to nuclei undergoing gamma emission, is true or not.

Concept Introduction:

Half-life is defined as a time required for decaying one-half part of any sample which is a radioactive material. Some elements are having isotopes that decay and disappear in a day while some can remain radioactive for billions of years. It can be calculated as below:

${\left(\frac{1}{2}\right)}^{\text{X}}$ where x is the number of half-life and the value comes as sample remains after decay.

Interpretation Introduction

(c)

Interpretation:

To analyse whether the given statement - At the end of two half-lives, one-half of the original radioactive sample remains; at the end of three half-lives, one-third of the original sample remains, is true or not.

Concept Introduction:

Half-life is defined as a time required for decaying one-half part of any sample which is a radioactive material. Some elements are having isotopes that decay and disappear in a day while some can remain radioactive for billions of years. It can be calculated as below:

${\left(\frac{1}{2}\right)}^{\text{X}}$ where x is the number of half-life and the value comes as sample remains after decay.

Interpretation Introduction

(d)

Interpretation:

To analyse whether the given statement - If the half-life of a particular radioactive sample is 12 minutes, a time of 36 minutes represnts three half-lives, is true or not.

Concept Introduction:

Half-life is defined as a time required for decaying one-half part of any sample which is a radioactive material. Some elements are having isotopes that decay and disappear in a day while some can remain radioactive for billions of years. It can be calculated as below:

${\left(\frac{1}{2}\right)}^{\text{X}}$ where x is the number of half-life and the value comes as sample remains after decay.

Interpretation Introduction

(e)

Interpretation:

To analyse whether the given statement - At the end of three half-lives, only 12.5% of anoriginal radioactive sample remains, is true or not.

Concept Introduction:

Half-life is defined as a time required for decaying one-half part of any sample which is a radioactive material. Some elements are having isotopes that decay and disappear in a day while some can remain radioactive for billions of years. It can be calculated as below:

${\left(\frac{1}{2}\right)}^{\text{X}}$ where x is the number of half-life and the value comes as sample remains after decay.