Mass and energy: E = mc²

Answer Key - Grade 11 Science Worksheet - Building Confidence

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

1. 1.

   With c = 2.99792458 × 10⁸ m/s, how much energy equals 1 kg of mass, in units of 10¹⁶ J, to 0.01, Ari?

   8.99 × 10¹⁶ J
2. 2.

   With c = 2.99792458 × 10⁸ m/s, how much energy equals 2 kg of mass, in units of 10¹⁶ J, to 0.01, Bo?

   17.98 × 10¹⁶ J

3. Read this first

   Use this

   The products have slightly less mass.

5. 3.

   In the photon diagram, which has more mass in total, Jun?

   • The starting nuclei
   • They have equal mass
   • The products
6. 4.

   In the photon diagram, what happens to the missing mass, Kira?

   Use the picture in question 3.

   • It hides inside the neutron
   • It is left behind as dust
   • It is released as energy
7. 5.

   What powers the Sun, Milo?

   • Fusing hydrogen into helium
   • Splitting uranium nuclei
   • Burning coal in its core
8. 6.

   What do today's nuclear power plants use to make energy, Noah?

   • Splitting uranium nuclei
   • Fusing hydrogen nuclei
   • Burning oil in the reactor
9. 7.

   In a nuclear power plant, what does the energy from fission do first, Pia?

   • Heats water into steam
   • Lights bulbs on its own
   • Charges batteries
10. 8.

    What does E = mc² say, Ren?

    • Mass can change into energy
    • Energy is mass times sound's speed
    • Mass and energy are unrelated
11. 9.

    Why does a tiny mass give a huge energy in E = mc², Tala?

    • c² is a very big number
    • Mass is measured in tonnes
    • Energy is measured in grams
12. 10.

    In a fusion reaction, how much of the mass becomes energy, Zee?

    • Most of it
    • A tiny fraction, under 1%
    • About half