Mass and energy: E = mc²
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
A power plant sends out 1000 MW of electrical power for 2 days. With c = 2.99792458 × 10⁸ m/s, how much mass equals that energy, to 0.01 g, Ari?
A power plant sends out 1000 MW of electrical power for 365 days. With c = 2.99792458 × 10⁸ m/s, how much mass equals that energy, to 0.01 g, Bo?
A power plant sends out 500 MW of electrical power for 30 days. With c = 2.99792458 × 10⁸ m/s, how much mass equals that energy, to 0.01 g, Esme?
Read this first
Photon diagram for a nucleus splitting
One neutron hits one uranium-235 nucleus, which splits into barium-141, krypton-92 and three neutrons. Total mass before: 236.052595 u. Total mass after: 235.866571 u.
In the photon diagram, how many neutrons come out for the one that went in, Jun?
- Two
- Three
- Just one
In the photon diagram, why can the freed neutrons keep a reactor running, Kira?
- They can split more uranium-235
- They add mass to the fuel
- They turn back into uranium
In the photon diagram, how does the total mass change, Luz?
- It drops by about 0.186 u
- It stays exactly the same
- It rises by about 0.186 u
Milo says fusion and fission make energy from nothing. Agree or disagree?
- Agree: E = mc² adds extra energy
- Disagree: lost mass becomes the energy
- Agree: nuclei create brand-new energy
Noah says a reactor turns its whole fuel mass into energy. Agree or disagree?
- Agree: E = mc² uses the whole mass
- Agree: the used fuel has no mass left
- Disagree: under 1% of the mass does
Pia says 1 kg of fusion fuel releases 1 kg × c² of energy. Agree or disagree?
- Disagree: only about 0.4% of it changes
- Agree: E = mc² uses the whole kilogram
- Agree: the fuel vanishes as energy
Per kilogram of fuel, which gives more energy: D–T fusion or uranium-235 fission, Tala?
- Both give the same amount
- Fission, by about 10 times or more
- Fusion, by about 4 to 5 times