Energy changes when charges or magnets move in a field
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Like charges of 20 nC and 30 nC, let go 4 cm apart, push apart to 10 cm. With k = 8.9875 × 10⁹ N·m²/C², how many μJ become kinetic energy, Ari?
Like charges of 10 nC and 50 nC, let go 2 cm apart, push apart to 5 cm. With k = 8.9875 × 10⁹ N·m²/C², how many μJ become kinetic energy, Esme?
Released magnets had 0.06 J stored. Just as they circle together they have 0.05 J of kinetic energy. Where is the rest, Jun?
- Still stored in the magnets
- It was destroyed
- In sound and a little heat
It takes 0.09 J of work to pull two magnets apart slowly. How much energy is stored in their field, Kira?
- 0.18 J
- 0.045 J
- 0.09 J
Two equal magnets pulled apart store 0.08 J, then are let go. Ignoring friction, how much kinetic energy do they have together just before meeting, Luz?
- 0.08 J
- 0.16 J
- 0.04 J
Noah says unlike charges lose field energy as they are pulled apart. Agree or disagree?
- Agree: the charges get weaker
- Agree: pulling apart releases it
- Disagree: they gain field energy
Pia says two like charges held close together store energy that is released when they are let go. Agree or disagree?
- Disagree: like charges store no energy
- Disagree: they pull together when released
- Agree: they push apart and speed up
A camera flash charges a capacitor, then empties it to make the flash. Where is the energy stored before the flash, Ren?
- In the light bulb
- In the electric field between the plates
- In the plastic case
A cupboard has a magnetic latch. When is field energy released, Tala?
- When the door stands still
- When the door snaps shut
- When the door is pulled open
In a small electric motor, what do the magnetic forces turn electrical energy into, Zee?
- Kinetic energy of the spinning part
- Chemical energy in the magnets
- Light