Fission, fusion and how radiation is used

Answer Key - Grade 10 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   A neutron splits uranium with mass number 235 into barium with mass number 141, krypton and 3 neutrons. What is the krypton's mass number, Ari?

   92
2. 2.

   A neutron splits uranium with mass number 235 into xenon with mass number 140, strontium and 2 neutrons. What is the strontium's mass number, Bo?

   94
3. 3.

   A neutron splits uranium with mass number 235 into barium with mass number 144, krypton and 3 neutrons. What is the krypton's mass number, Esme?

   89
4. 4.

   Which process joins light nuclei together, Jun?

   • Alpha decay
   • Fission
   • Fusion
5. 5.

   What does a uranium-235 fission produce, Kira?

   • Two medium nuclei and neutrons
   • Hydrogen gas and water
   • One helium nucleus by itself
6. 6.

   Which process happens naturally only at extremely high temperatures, like the Sun's core, Luz?

   • Fission
   • Beta decay
   • Fusion
7. 7.

   Where does the energy released in fission come from, Noah?

   • Burning the uranium in air
   • Heat stored from the Sun
   • A tiny loss of mass, E = mc²
8. 8.

   Fission of uranium-235 gives about 8 × 10⁷ kJ per gram; Sun fusion gives about 6.4 × 10⁸ kJ per gram of hydrogen. Which gives more per gram, and about how many times more, Pia?

   • Fusion gives about 8 times more
   • They give the same
   • Fission gives about 8 times more
9. 9.

   Uranium-235 + neutron → xenon-140 + strontium-94 + ? Which completes it, Ren?

   • 1 neutron
   • 3 neutrons
   • 2 neutrons
10. 10.

    Barium (56 protons) and krypton (36 protons) come from splitting uranium. Do their atomic numbers balance, Tala?

    • No: they add to 141
    • No: they add to 236
    • Yes: 56 + 36 = 92