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Modern Physics

97 MCQ questions with answers and explanations · page 1 of 4

Test yourself▶ 25 question test▶ 50 question test

Q1. A beam of light which is highly directional is called-

  1. AEraser
  2. BGrazer
  3. CMesser
  4. DLaser
Show answer & explanation

Answer: D) Laser

Q2. The laser beam is always-

  1. AConvergent beam
  2. BDiverging beam
  3. Cparallel beam
  4. Dparallel at first and then divergent
Show answer & explanation

Answer: B) Diverging beam

Q3. The nucleus of an atom contains-

  1. Aprotons and electrons
  2. Bneutrons and electrons
  3. Cjust electrons
  4. Dneutrons and electrons
Show answer & explanation

Answer: A) protons and electrons

Q4. Neutron was discovered by-

  1. ARutherford
  2. BThomson
  3. CChadwick
  4. DNewton
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Answer: C) Chadwick

Q5. The temporary particle in the following is-

  1. AProton
  2. Belectron
  3. CNeutron
  4. Dalpha particles
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Answer: C) Neutron

Q6. What is the mass number of an element whose atom has two protons, two neutrons and two electrons?

  1. A2
  2. B4
  3. C6
  4. D8
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Answer: B) 4

Q7. The shape of the nucleus is-

  1. A10-10 m.
  2. B10 m.
  3. C10-13 m.
  4. D10-15 m.
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Answer: D) 10-15 m.

Q8. Who discovered the positron?

  1. ARutherford
  2. BThomson
  3. CChadwick
  4. DAnderson
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Answer: D) Anderson

Q9. Find the number of protons in the nucleus of a hydrogen atom.

  1. AZero
  2. BOne
  3. CThree
  4. Dfive
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Answer: B) One

Q10. The electron was discovered by-

  1. AThomson
  2. BJames Watt
  3. CGalileo
  4. DRutherford
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Answer: A) Thomson

Q11. The atomic number of an element is the number of...

  1. Aneutrons in the nucleus
  2. Belectrons in the nucleus
  3. Cprotons in the nucleus
  4. Dnone of these
Show answer & explanation

Answer: C) protons in the nucleus

Q12. Protons reside in the atom-

  1. Awithin the nucleus
  2. Boutside the nucleus
  3. Cin the orbital
  4. Dboth in the nucleus and in the orbitals
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Answer: A) within the nucleus

Q13. Carries electrons-

  1. Aone unit negative charge
  2. Bone unit positive charge
  3. Ctwo units of negative charge
  4. Dtwo units of positive charge
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Answer: A) one unit negative charge

Q14. In isotopic atoms-

  1. Ahave the same number of protons
  2. Bhave the same number of neutrons
  3. Chave the same number of nucleons
  4. DAll are true
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Answer: A) have the same number of protons

Q15. Isotopes are atoms of the same element that have

  1. ASame atomic weight but different atomic number
  2. BDifferent atomic weights but same atomic number
  3. CBoth atomic mass and atomic number are the same.
  4. Dnone of the above
Show answer & explanation

Answer: B) Different atomic weights but same atomic number

Q16. An isotope of an atomic nucleus is that nucleus in which-

  1. AThe number of neutrons is the same, but the number of protons is different
  2. BThe number of protons is the same, but the number of neutrons is different.
  3. CThe number of both protons and neutrons remains the same.
  4. DBoth protons and neutrons have different numbers.
Show answer & explanation

Answer: B) The number of protons is the same, but the number of neutrons is different.

Q17. Two elements having different number of electrons but same mass number are called-

  1. Aisotopes
  2. Bisobar
  3. Cisomer
  4. Dsumneutronic
Show answer & explanation

Answer: B) isobar

Q18. Atoms having the same atomic number but different atomic masses are called-

  1. Aisobar
  2. Bisotopes
  3. CIsobars
  4. DNone of these
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Answer: B) isotopes

Q19. Which element has the most isotopes?

  1. AUranium
  2. BRadium
  3. Chydrogen
  4. DCesium
Show answer & explanation

Answer: D) Cesium

Q20. What are atoms called that have the same number of protons but different numbers of neutrons?

  1. Aisobaric
  2. Bisomer
  3. Csumneutronic
  4. Disotopes
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Answer: D) isotopes

Q21. The process of splitting of a heavy nucleus into two lighter nuclei is called-

  1. Anuclear fusion
  2. Bnuclear fission
  3. Cradioactive disintegration
  4. DMass damage
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Answer: B) nuclear fission

Q22. The following principle works in the atomic bomb:

  1. Anuclear fusion
  2. Bnuclear fission
  3. CFleming's Law
  4. Dphotoelectric effect
Show answer & explanation

Answer: B) nuclear fission

Q23. Hydrogen bomb is based on-

  1. Aon nuclear fusion
  2. Bon nuclear fission
  3. Con all of the above
  4. Don all of the above
Show answer & explanation

Answer: A) on nuclear fusion

Q24. The first nuclear reactor was built by-

  1. AEinstein
  2. BNewton
  3. CRutherford
  4. DFermi
Show answer & explanation

Answer: D) Fermi

Q25. The principle of atomic bomb is based on—

  1. Aon nuclear fusion
  2. Bon nuclear fission
  3. Con both of the above
  4. Dnone of these
Show answer & explanation

Answer: B) on nuclear fission

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