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Nuclear physics

Class 12 · Physics · 6 questions

Name: ____________________   Date: ____________

  1. Binding energy of a nucleus is the energy needed to:

    • A Heat it
    • B Rotate it
    • C Add an electron
    • D Separate it into nucleons
  2. The mass defect is the difference between the:

    • A Mass of two atoms
    • B Mass of separate nucleons and the nucleus
    • C Charge and mass
    • D Atomic and mass number
  3. A radioactive sample has a half life of 5 hours. After 15 hours the fraction left is:

    • A 1/2
    • B 1/4
    • C 1/8
    • D 1/3
  4. Beta decay increases the atomic number by:

    • A 0
    • B 1
    • C 4
    • D 2
  5. A fission chain reaction is controlled in a reactor using:

    • A Water only
    • B More uranium
    • C Air
    • D Control rods
  6. The energy released from 1 atomic mass unit converted completely is about:

    • A 9310 MeV
    • B 931 MeV
    • C 9.31 MeV
    • D 93 MeV

Answer key

1. D, 2. B, 3. C, 4. B, 5. D, 6. B

  1. It is the energy that holds the nucleons together.

  2. The nucleus is lighter than the sum of its nucleons.

  3. Three half lives: (1/2)^3 = 1/8.

  4. In beta minus decay a neutron changes into a proton.

  5. Control rods absorb neutrons.

  6. 1 u corresponds to about 931 MeV.