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Radioactivity

57 MCQ questions with answers and explanations · page 1 of 3

Test yourself▶ 25 question test▶ 50 question test

Q1. Who discovered 'radioactivity'?

  1. ARutherford
  2. BHenri Becquerel
  3. CRoentgen
  4. DEinstein
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Answer: B) Henri Becquerel

Q2. Radioactivity is a property of what?

  1. Aof electrons
  2. Bof protons
  3. Cof neutrons
  4. Dof the nucleus
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Answer: D) of the nucleus

Q3. Participates in radioactive changes-

  1. Avalence electrons of an atom
  2. Bcore electrons of an atom
  3. Cnucleus of an atom
  4. Dnone of these
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Answer: C) nucleus of an atom

Q4. The number of protons in the stable nucleus of an atom is-

  1. Aequal to the number of neutrons
  2. Bmore than the number of neutrons
  3. Cless than the number of neutrons
  4. Dnone of these
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Answer: C) less than the number of neutrons

Q5. What is the unit of radioactivity?

  1. AAngstrom
  2. BCandela
  3. CFermi
  4. DCurie
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Answer: D) Curie

Q6. What do radioactive elements emit?

  1. Aultraviolet rays
  2. Bα, β and γ radiation
  3. Cradio waves
  4. Dinfrared waves
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Answer: B) α, β and γ radiation

Q7. Who discovered alpha and beta rays?

  1. ADalton
  2. BRoentgen
  3. CRutherford
  4. DWillard
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Answer: C) Rutherford

Q8. Which scientist discovered gamma rays?

  1. APaul Willard
  2. BRutherford
  3. CRoentgen
  4. DDalton
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Answer: A) Paul Willard

Q9. Which of the following radioactive rays is equivalent to a helium nucleus?

  1. Aalpha rays
  2. Bbeta rays
  3. CGamma rays
  4. DNone of these
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Answer: A) alpha rays

Q10. Which of the radiations emitted from the nucleus has the highest penetrating power?

  1. Aof alpha rays
  2. Bof beta rays
  3. Cof gamma rays
  4. Dnone of these
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Answer: C) of gamma rays

Q11. 'Alpha' (α) rays are-

  1. AH⁺ ions
  2. BHe⁺⁺ion
  3. Celectron
  4. DProton
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Answer: B) He⁺⁺ion

Q12. The charge present on alpha rays is-

  1. Atwo units of positive charge
  2. Bunit negative charge
  3. Cunit positive charge
  4. Dnone of these
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Answer: A) two units of positive charge

Q13. β-rays are made up of-

  1. Afrom positively charged particles
  2. Bfrom negatively charged particles
  3. Cfrom neutral particles
  4. Dnone of these
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Answer: B) from negatively charged particles

Q14. Isobars are formed by the emission of which of the following?

  1. Aalpha rays
  2. Bbeta rays
  3. CGamma rays
  4. DX-rays
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Answer: B) beta rays

Q15. The emission of which of the following increases the atomic number of an element by one?

  1. Aalpha particles
  2. Bbeta particles
  3. CProton
  4. DNeutron
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Answer: B) beta particles

Q16. Which of the following has a negative charge?

  1. Aalpha rays
  2. Bbeta rays
  3. CGamma rays
  4. DX-rays
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Answer: B) beta rays

Q17. What is the analog of electron?

  1. Aα-particles
  2. Bβ-particles
  3. Cγ-particles
  4. DH-atom
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Answer: B) β-particles

Q18. Beta rays have greater penetrating power than alpha rays of the same energy because-

  1. Aβ-rays are made up of negatively charged electrons
  2. Bβ-rays have a high velocity because their mass is negligible.
  3. Cα-rays are positively charged and have a charge of 2 units.
  4. Dβ-rays are repelled by the electron cloud, while α-rays are attracted.
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Answer: B) β-rays have a high velocity because their mass is negligible.

Q19. What type of charge do β-rays carry?

  1. Apositive
  2. Bnegative
  3. CZero charge
  4. DNone of these
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Answer: B) negative

Q20. What are γ-rays made of?

  1. Ameson particle
  2. Bneutrino particle
  3. CHiggs boson
  4. Delectromagnetic waves
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Answer: D) electromagnetic waves

Q21. What are gamma rays?

  1. Acharged particles coming from outer space
  2. Bhigh-energy, uncharged rays from outer space
  3. Chigh-energy rays emitted by radioactive materials
  4. Duncharged particles emitted by radioactive substances
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Answer: C) high-energy rays emitted by radioactive materials

Q22. Which of the following rays has the greatest penetrating power?

  1. Aof α-rays
  2. Bof β-rays
  3. Cof γ-rays
  4. DNone of these
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Answer: C) of γ-rays

Q23. Which of the following rays has the lowest ionizing power?

  1. Aof α-rays
  2. Bof β-rays
  3. Cof γ-rays
  4. DNone of these
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Answer: C) of γ-rays

Q24. Which of the following rays has the highest ionizing power?

  1. Aof α-rays
  2. Bof β-rays
  3. Cof γ-rays
  4. DNone of these
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Answer: A) of α-rays

Q25. What do all radioactive substances finally turn into after decay?

  1. ACorundum
  2. Blead
  3. CCadmium
  4. Dzinc
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Answer: B) lead

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