Tag: nuclear chemistry and radioactivity

Questions Related to nuclear chemistry and radioactivity

The radioactive isotope used in the treatment of cancer has to be a good source of ________ radiations.

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. $\beta$

  2. $\alpha$

  3. $\gamma$

  4. $IR$

Show answer
Correct Option: C
Explanation:

X-rays, gamma rays and beta particles are all used in medicine to treat internal organs. X-rays are produced by firing electrons at a metal target and gamma rays are emitted by the nucleus of radioactive atoms. Gamma rays are used to kill cancer cells, to sterilize medical equipment and in radioactive tracers.

Match the following

List - I List - II
A) Functioning of Thyroid gland  I) Cobalt - 60
B) Blood disorders  II) Iodine - 131
C) Cancer  III) Sulphur - 35
D) Transportation of minerals in plants  IV) radio phosphorus
V) radio sodium
chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. A-I,III B- II,IV C-III,V D-IV

  2. A-II B-IV,V C-I D-III

  3. A-I B-II C-IV D-III

  4. A-II B-I C-III D-IV

Show answer
Correct Option: B
Explanation:

 1.Iodine - 131 it is use for functioning of Thyroid gland. It detect using radio active Iodine - 131

2.Radioactive phosphorus is known as P-32. It is a radioactive form of sodium phosphate. It is used as a treatment for some blood disorders.

3.Cobalt therapy or cobalt-60 therapy is the medical use of gamma rays from the radioisotope cobalt-60 to treat conditions such as cancer.

4.The sulfate ions in the solution contained radioactive sulfur atoms – 35 S. The purpose of this investigation was to investigate active transport, that is, a process that uses energy to transport useful substances across cell membranes.

 

The count rate observed from a radioactive source at $t$ second was $N _0$ and at $4t$ second it was $\dfrac{N _0}{16}$. The count rate observed at $\left(\dfrac{11}{2}\right)t$ second will be

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. $\dfrac{N _0}{128}$

  2. $\dfrac{N _0}{64}$

  3. $\dfrac{N _0}{32}$

  4. $None\ of\ these$

Show answer
Correct Option: B
Explanation:
after n lives,

$N=N _0\left ( \dfrac{1}{2} \right )$

initially,

$t=t$

$t=4t-t=3t$

$\dfrac{N _0}{16}=N _0\left ( \dfrac{1}{2} \right )^n$

$n=4$

$4t _{\frac{1}{2}}=3t$

$\Rightarrow t _{\frac{1}{2}}=\dfrac{3}{4}t$

$\lambda =\dfrac{\ln 2}{t _{\frac{1}{2}}}=\dfrac{4\ln 2}{3t}$

at $t=\dfrac{11}{2}ts$

$t=\dfrac{11}{2}t-t=\dfrac{9}{2}t$

$N=N _0e^{-\lambda \frac{9}{2}t}$

$N=N _0e^{-\lambda \frac{4\ln 2}{3t}\times \frac{9}{2}t}$

$N=N _0e^{-6\ln 2}$

$N=N _0e^{\ln \frac{1}{2^6}}$

$N=\dfrac {N _0}{2^6}=\dfrac {N _0}{64}$

After $280$ days, the activity of a radioactive sample is $6000 dps$. The activity reduces to $3000 dps$ after another $140 days$. The initial activity of the sample in $dps$ is:

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. $6000$

  2. $9000$

  3. $3000$

  4. $24000$

Show answer
Correct Option: D
Explanation:

Here, the activity of the radioactive sample reduces to half in $140$ days. Therefore, the half life of the sample is $140$ days. $280$ days is it's two half lives. So before two half lives it's activity was

${2^6} \times 6000 = 24000\,dps.$
Hence, the option $D$ is the correct answer.

The specific activity (per gm) of radium is nearly-

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. 1 Bq

  2. 11 Ci

  3. $ 3.7 \times 10^{10} Bq$

  4. 1 m Ci

Show answer
Correct Option: C

The radioactivity of an old sample of a liquid due to tritium (half life $12.5$ years) was found to be only about $3$% of that measured in a recently purchased bottle marked $7$ year old. The sample must have been prepared about:

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. $70$ year

  2. $63.24$ year

  3. $420$ year

  4. $300$ year

Show answer
Correct Option: B
Explanation:

$\begin{array}{l} Hence, \ \frac { N }{ { { N _{ 0 } } } } =0.03=\left( { -\lambda t } \right)  \ In\left( { 0.03 } \right) =-\lambda t=\frac { { -In\left( 2 \right) \times t } }{ { \frac { { { T _{ 1 } } } }{ 2 }  } }  \ t=\frac { { In\left( { 0.03 } \right) \times \frac { { { T _{ 1 } } } }{ 2 }  } }{ { -In\left( 2 \right)  } } =63.24\, years \end{array}$

Hence,
option $(B)$ is correct answer.

Radioactive nuclei injected into a patient collect at certain sites within the body,undergo radioactive decay and emit electromagnetic radiation.These radiations can then be recorded by a detector.This procedure provides an important diagnostic toll called

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. Gamma camera

  2. CAT scan

  3. Radio tracer technique

  4. Gamma ray spectroscopy

Show answer
Correct Option: C
Explanation:

Tracers are a common application of radioisotopes. A tracer is a radioactive element whose pathway through which a chemical reaction can be followed. Tracers are commonly used in the medical field and in the study of plants and animals. Radioactive Iodine-131 can be used to study the function of the thyroid gland assisting in detecting disease.

Fill in the blanks :

The mass of a body remains constant till the velocity of body is ............

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. much less than the velocity of light

  2. equal to velocity of light

  3. much higher than the velocity of light

  4. none of the above

Show answer
Correct Option: A
Explanation:

According to Einstein if a body moves almost more than the velocity of light then it starts losing its mass.He gave this concept by a formula that is $E=m c^{2}$.Hence for the body to maintain constant mass it has to move with the speed less than the velocity of light.

The atomic number of natural radioactive element is .....................

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. greater than 82

  2. less than 82

  3. not defined

  4. atleast 92

Show answer
Correct Option: A
Explanation:

A

All elements with atomic numbers greater than 83 are radio isotope meaning that these elements have unstable nuclei and are radioactive. 

Which of the following can be diagnosed by Iodine-131 radioisotope?

chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

  1. Kidneys

  2. Heart

  3. Lungs

  4. Thyroid

  5. Bone marrow

Show answer
Correct Option: D
Explanation:

Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland. Thus the health problem related to thyroid can be diagnosed by Iodine−131 radioisotope.