Tag: chemistry

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Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

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

  1. Kidneys

  2. Heart

  3. Lungs

  4. Thyroid

  5. Bone marrow
Reveal answer Fill a bubble to check yourself
D Correct answer
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. 

Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

The electromagnetic radiation observed in Radioactivity is ..............

  1. $\alpha$ - particle
  2. $\beta$ - particle
  3. $\gamma$ - rays

  4. X - rays
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gamma ray (also called gamma radiation) is penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei. It consists of photons in the highest observed range of photon energy.

Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

Which of the following statements are true?

  1. The nucleus of an atom becomes radioactive when A - Z is more than Z

  2. Isotopes having radioactive properties are called radio isotopes

  3. Radio isotopes can be prepared artifically by nuclear transmutation

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atoms having radioactive properties are called radio isotopes. The nucleus of an atom becomes radioactive when the number of neutrons in the nucleus exceeds the number of protons inside it. $ _{6}C^{14},  _{27}Co^{60},  _{6}C^{12},  _{19}K^{40}$ etc are all examples of naturally occurring radio isotopes. However, they can also be prepared artificially by nuclear transmutation.

Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

The age of fossils can be estimated with the help of which radioisotope?

  1. $ _{6}C^{14}$
  2. $ _{27}Co^{60}$
  3. $ _{6}C^{12}$
  4. $ _{19}K^{40}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The age of fossils can be estimated by the study of decay of radioactive carbon atom $ _{6}C^{14}$ in the remains of the dead and decaying material. This process is called carbon dating.

Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

Which of the following is used by an archaeologist to determine the age of an artifact, in percentage?

  1. $Carbon-14$
  2. $Phosphorus-31$
  3. $Hydrogen-3$
  4. $Chlorine-37$
  5. $Bromine-81$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbon−14 is used by an archaeologist to determine the age of an artifact, in percentage.
The ratio C-14 / C-12 in fresh sample is compared with the ratio in dead sample.

Multiple choice chemistry nuclear physics types of radioactivity nuclear chemistry and radioactivity radioactivity

The radioactivity of a sample is $R _ { 1 } $at a time $T _ { 1 }$ and $R _ 2$ at a time $ T _ 2 $ . If the half-life of the specimen is T  ,  the number of atoms that have disintegrated in the time $T _ 2 - T _  1 $ is proportional to 

  1. $T _2-T _1\alpha(R _1-R _2)T$
  2. $\left( R _ { 1 } - R _ { 2 } \right)$
  3. $\left( R _ { 1 } - R _ { 2 } \right) / T$
  4. $\left( R _ { 1 } - R _ { 2 } \right) T$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
[D]
$\begin{array}{l} { R _{ 1 } }=\lambda { N _{ 1 } } \\ { R _{ 2 } }=\lambda { N _{ 2 } } \end{array}$
Number of atoms disintegrated in time 
$\begin{array}{l} { T _{ 2 } }-{ T _{ 1 } }={ N _{ 1 } }-{ N _{ 2 } }=\dfrac { { { R _{ 1 } }-{ R _{ 2 } } } }{ \lambda  }  \\ \lambda =\dfrac { { 0.693 } }{ T }  \\ { T _{ 2 } }-{ T _{ 1 } }=\dfrac { { { R _{ 1 } }-{ R _{ 2 } }\times T } }{ { 0.693 } }  \\ { T _{ 2 } }-{ T _{ 1 } }\alpha \left( { { R _{ 1 } }-{ R _{ 2 } } } \right) T \end{array}$