Chirkut.বাংলা

MCQ practice · SSC Physics Board questions · Chapter 4: Work, Power and Energy

Rajshahi Board 2023

In the case of uranium-

  1. i. its amount in nature is 0.7%
  2. ii. it has 143 protons and 92 neutrons
  3. iii. it has 92 protons and 143 neutrons

Think it through first, then pick an option.

  1. a i and ii
  2. b ii and iii
  3. c i and iii
  4. d i, ii and iii
Answer and explanation

Correct answer: c i and iii

i true: Only 0.7% of natural uranium is uranium 235. ii false: Uranium 235 has 92 protons, not 143; the protons and neutrons are swapped. iii true: 92 protons and 143 neutrons (235 − 92 = 143), as in the book.

Why the other options are wrong

  • a i and ii: This is not the answer; the right combination is i and iii. i true: Only 0.7% of natural uranium is uranium 235. ii false: Uranium 235 has 92 protons, not 143; the protons and neutrons are swapped. iii true: 92 protons and 143 neutrons (235 − 92 = 143), as in the book.
  • b ii and iii: This is not the answer; the right combination is i and iii. i true: Only 0.7% of natural uranium is uranium 235. ii false: Uranium 235 has 92 protons, not 143; the protons and neutrons are swapped. iii true: 92 protons and 143 neutrons (235 − 92 = 143), as in the book.
  • d i, ii and iii: This is not the answer; the right combination is i and iii. i true: Only 0.7% of natural uranium is uranium 235. ii false: Uranium 235 has 92 protons, not 143; the protons and neutrons are swapped. iii true: 92 protons and 143 neutrons (235 − 92 = 143), as in the book.