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Modern Physics

97 MCQ questions with answers and explanations · page 2 of 4

Test yourself▶ 25 question test▶ 50 question test

Q26. The age of the oldest style group is estimated.

  1. AIn the K-Ar method
  2. Bby the uranium-lead method
  3. CBy Ra-Si method
  4. DC 14by method
Show answer & explanation

Answer: A) In the K-Ar method

Q27. emits radioactive substances.

  1. Aalpha rays
  2. Bbeta rays
  3. Cgamma rays
  4. DAll of the above
Show answer & explanation

Answer: D) All of the above

Q28. Energy is produced in the Sun by-

  1. Aby nuclear fission
  2. Bby nuclear fusion
  3. Cby oxidation reactions
  4. Dby reduction reactions
Show answer & explanation

Answer: B) by nuclear fusion

Q29. Which of the following has a negative charge?

  1. AX-rays
  2. Ba - particle
  3. CB particles
  4. Dy-particle
Show answer & explanation

Answer: C) B particles

Q30. The difference between a nuclear reactor and an atomic bomb is that-

  1. AThere is no chain reaction in a nuclear reactor whereas there is in an atomic bomb.
  2. BThe chain reaction in a nuclear reactor is controlled by
  3. CThe chain reaction in a nuclear reactor is not controlled.
  4. DThere is no chain reaction in an atomic bomb whereas there is in a nuclear reactor.
Show answer & explanation

Answer: B) The chain reaction in a nuclear reactor is controlled by

Q31. Which one of the following is essential in the construction of a nuclear reactor?

  1. ACobalt
  2. BNickel
  3. CZirconium
  4. Dtungsten
Show answer & explanation

Answer: C) Zirconium

Q32. The alpha particle has two units of positive charge. Its mass is approximately equal to-

  1. Aof two protons
  2. Bof an atom of helium
  3. CThe sum of the masses of two positrons and two neutrons
  4. Dof two positrons because each positron has only one positive charge.
Show answer & explanation

Answer: B) of an atom of helium

Q33. Cobalt-60 is commonly used in radiation therapy because it emits-

  1. Aalpha rays
  2. BVita Rays
  3. Cgamma rays
  4. DX-rays
Show answer & explanation

Answer: C) gamma rays

Q34. Which of the following is used as a neutron moderator in a nuclear reactor?

  1. Aheavy water
  2. Bgraphite
  3. CCadmium
  4. Daluminium
Show answer & explanation

Answer: C) Cadmium

Q35. In the production of X-rays-

  1. Aproduction of X-rays
  2. Bnuclear fission in practice
  3. Cthermonuclear fusion in operation
  4. DIn nuclear acceleration
Show answer & explanation

Answer: B) nuclear fission in practice

Q36. Curie is the name of whose unit?

  1. Aradioactivity
  2. Btemperature
  3. Cheat
  4. Denergy
Show answer & explanation

Answer: A) radioactivity

Q37. Energy is produced in nuclear reactors by-

  1. Aby controlled fusion
  2. Bby uncontrolled fusion
  3. Cby controlled fission
  4. Dby uncontrolled fission
Show answer & explanation

Answer: C) by controlled fission

Q38. Why is nuclear fusion also called thermonuclear reaction?

  1. AFusion converts nuclear energy into heat
  2. BFusion requires extremely high temperature conditions.
  3. CA lot of heat is produced during fusion.
  4. Dnone of these
Show answer & explanation

Answer: C) A lot of heat is produced during fusion.

Q39. Radiocarbon dating is used to determine age.

  1. APlanets
  2. Bfossils
  3. Cbabies
  4. Drocks
Show answer & explanation

Answer: B) fossils

Q40. What is a nuclear reactor?

  1. Aatomic bomb manufacturing site
  2. Bheavy water lock
  3. Cemitter of U-238
  4. Datomic reactor
Show answer & explanation

Answer: D) atomic reactor

Q41. The age of the Earth is determined by which of the following methods?

  1. Acarbon dating method
  2. BBiotechnological method
  3. Cbiological clock method
  4. DUranium method
Show answer & explanation

Answer: D) Uranium method

Q42. Consider the following statements: Assertion (A) Ernest Rutherford stated before the Royal Society that nuclear power would never be available to mankind. Reason (R) He believed that Einstein's law would fail and matter would not be converted into energy. Select your level from the coding scheme given below:

  1. ABoth A and R are true and R is the correct reason
  2. BBoth A and R are true, but R is not the correct reason
  3. CA is true, but R is false.
  4. DA is false, but R is true
Show answer & explanation

Answer: A) Both A and R are true and R is the correct reason

Q43. The energy of the sun is produced by-

  1. Aby ionization
  2. Bby nuclear fusion
  3. Cby oxidation
  4. Dby oxidation
Show answer & explanation

Answer: B) by nuclear fusion

Q44. Which of the following is used as a coolant in the Fast Breeder Test Reactor at Kalpakkam?

  1. Acarbon dioxide
  2. Bheavy water
  3. Csea water
  4. Dmolten sodium
Show answer & explanation

Answer: D) molten sodium

Q45. Stars obtain their energy from- 1. Nuclear fusion 2. Gravitational contraction 3. Chemical reaction 4. Nuclear fission

  1. A1 and 2
  2. B1, 2 and 3
  3. C1 and 4
  4. D2 and 4
Show answer & explanation

Answer: A) 1 and 2

Q46. Heavy water (D) in nuclear reactors2In what form is O used?

  1. Adiluent
  2. Bcoolant
  3. Cpreservative
  4. Dcontroller
Show answer & explanation

Answer: A) diluent

Q47. Match List-I with List-II and select the correct answer using the code given below the lists. List-I (Radioisotopes) List-II (Diagnostic uses) A. Arsenic-74 1. Hyperactivity of thyroid gland B. Cobalt 60 2. Blood disorders C. Iodine-131 3. Tumor D. Sodium-24 4. Cancer

  1. AABCD 1 2 3 4
  2. BABCD 4 3 1 2
  3. CABCD 3 4 1 2
  4. DABCD 4 3 2 1
Show answer & explanation

Answer: C) ABCD 3 4 1 2

Q48. Whose conclusion is the mass energy relation?

  1. Aquantum theory
  2. Bgeneral theory of relativity
  3. CField theory of energy
  4. DSpecial theory of relativity
Show answer & explanation

Answer: B) general theory of relativity

Q49. Which device is used to convert solar energy into electricity?

  1. Aelectrochemical cell
  2. BGalvanic cell
  3. CPhotovoltaic cell
  4. DDaniel Sale
Show answer & explanation

Answer: C) Photovoltaic cell

Q50. Barium is fed to patients in a suitable form before abdominal X-ray examination because-

  1. ABarium allows X-rays to pass through the stomach due to its transparency to X-rays.
  2. BVarium compounds, like magnesium sulfate, help clear the stomach before X-ray examinations.
  3. CBarium is a good absorber of X-rays and this helps the stomach (compared to other areas) to be seen more clearly in the image.
  4. DBarium salts are white in color and this helps the stomach to be seen more clearly in the image than other areas.
Show answer & explanation

Answer: C) Barium is a good absorber of X-rays and this helps the stomach (compared to other areas) to be seen more clearly in the image.

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