Mass and energy: E = mc²
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
Deuterium and tritium (total mass 5.030151 u) fuse into helium-4 and a neutron (total 5.011268 u). With 1 u = 931.494 MeV, what energy is released, to 0.01 MeV, Ari?
In the Sun's core, four hydrogen-1 atoms (total 4.0313 u) end up as one helium-4 atom (4.002603 u). With 1 u = 931.494 MeV, what energy is released, to 0.01 MeV, Bo?
Why do both fusion of light nuclei and fission of heavy nuclei release energy, Jun?
- Both make more tightly bound nuclei
- Both destroy protons
- Both of them create new mass from nothing
Which of these nuclei is among the most tightly bound per nucleon, Kira?
- Iron-56
- Uranium-238
- Hydrogen-2
Why can't iron be used as fuel for fusion or fission, Luz?
- It is magnetic
- Its nuclei are far too heavy to change
- It is near the peak of binding
The Sun gives out 3.828 × 10²⁶ W (NASA). Where does that energy come from, Milo?
- Burning like a fire
- Shrinking as it cools
- Mass lost in fusion
NASA lists the Sun's fusion mass loss as 4.26 × 10⁹ kg each second. Compared with its mass, 1.9885 × 10³⁰ kg, is that much, Noah?
- No: it is a tiny fraction
- Yes: it is more than its mass
- Yes: it is half each year
Which process joins nuclei, and which splits them, Ren?
- Fusion joins; fission splits
- Fission joins; fusion splits
- Both of them split nuclei
Which fuel do most fusion experiments on Earth use, Tala?
- Uranium-235
- Deuterium and tritium
- Coal and oxygen
Why is fusion hard to achieve on Earth, Zee?
- Fusion needs uranium
- Nuclei must be very hot to get close
- Hydrogen is too rare