MCQ on Redioisotopes - YB Study -->

MCQ on Redioisotopes

Radioisotopes MCQ with Answers Pdf

What are Radioisotopes?

  • In the periodic table, an element occupies a position. But scientists have found that the atoms of the same element are not exactly the same, some atoms are heavier, some are lighter; some atoms are very stable and will not change, and some atoms are radioactive and will change, and after decay become another atom of an element. 
  • We call these atoms in the same position but with different properties called isotopes. 
  • Some isotopes emit radiation, so they are called radioisotopes. 
  • Radioisotopes refer to nuclides with the same atomic number but different masses in an element that undergoes radioactive decay.


Radioisotopes have the following three properties:

  • First, it can emit a variety of different rays. Some emit alpha rays, some emit beta rays, some emit gamma rays, or both. And neutron rays. Among them, the alpha ray is a stream of alpha particles, with a positive charge, and the beta ray is a stream of electrons, with a negative charge.
  • Second, the emitted rays are determined by the different nuclei themselves. For example, each time a cobalt-60 nucleus decays, it emits three particles: a beta particle and two photons. Cobalt-60 eventually becomes stable nickel-60.
  • Third, it has a certain lifespan. The time it takes people to reduce the number of nuclei of a radioisotope that begins to exist is called the half-life. For example, the half-life of cobalt-60 is about 5 years.

Multiple Choice Questions on Radioisotopes

1. What are isotopes?

(1) Isotopes are elements having the same atomic number but differ in their mass number and chemical characteristics.

(2) Elements having the same atomic number but different mass numbers are called Isotopes 

(3) Both of these 

(4) None of these 

Answer: 3


2. The artificially produced radioactive elements are known as________

(1) ions

(2) radiant

(3) radioisotopes

(4) transmutations

Answer: 3


3. The half-life of a radioisotope is_____________

(1) half the time is taken for complete decay

(2) half the time is taken for half the decay

(3) time taken for complete decay

(4) time taken for half the decay

Answer: 4


4. Which of the following is radioactive?

(1) hydrogen sulfide

(2) vimentin

(3) tritium

(4) deuterium

Answer: 3


5. The half-life of Carbon-14 is_________

(1) 23 years

(2) 1000 years

(3) 1200 years

(4) 5730 years

Answer: 4


6. Isotopes of an element have a different number of________

(1) Proton

(2) Neutron

(3) Electron

(4) atom

Answer: 2


7. A compound containing some amount of radioisotope is_________

(1) tracer

(2) radioactive compound

(3) non-radioactive

(4) linear active compound

Answer: 1


8. The chemical compounds to explore the metabolism of chemical reactions inside the human body, animals, or plants containing some quantity of radioisotopes are called______

(1) radioactive endoscope

(2) radioactive tracers

(3) radioactive fusion

(4) radioactive atoms

Answer: B


9. Which of the following is not radioactive?

(1) Carbon

(2) deuterium

(3) tritium

(4) Sulphur 

Answer: 2


10. Which of the following enzyme is assayed and measured using the radioisotope method?

(1) Hydrolases

(2) Bacterial luciferase

(3) Phosphofructokinase

(4) Glutamate decarboxylase

Answer: 4


11. Which of the following is true for the radioisotope method?

(1) The intensity of emitted light is used to study enzyme reaction

(2) The reaction can be used to assay ATP and appropriate enzymes via coupled reaction

(3) It is restricted to the separation of radiolabeled forms of substrate and product

(4) Bacterial luciferase can be assayed and measured by this method

Answer: 3


12. The half-life period of a radioactive element depends on its_________                      

(1) temperature

(2) pressure

(3) amount

(4) None of the mentioned

Answer: 4


13. Which of the following is not true for the radioisotope method?

(1) This method is used in studying the mechanism of enzyme action and in ligand binding sites

(2) Change is absorbance is used as the basis for assaying enzyme

(3) If one product is gas, the method is easier

(4) Glutamate decarboxylase is assayed and measured using this method

Answer: 2


14. Which of the following statements about radioisotopes is correct______

(1) Like radioactive elements, radioisotopes have a certain half-life, and the law of decay is the same

(2) The decay of radioisotopes can produce another new element

(3) Radioisotopes can only be produced by natural decay and cannot be measured by artificial methods

(4) The above statement is not correct

Answer: 1

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