Answer: 1.6×10-19 J.
- A 1.6×10-19 W
- B 1.6×10-19 J
- C 9.1×10-31 J
- D 3.6×106 J
Correct answer: B. 1.6×10-19 J
Explanation: 1 eV is the energy gained by an electron across a 1 V potential difference: e × V = 1.6×10-19 C × 1 V = 1.6×10-19 J.
As a pendulum swings, total mechanical energy (KE+PE) stays constant: at the highest points A and C, all energy is potential (zero speed); at the lowest point B, all of that energy has converted into kinetic energy (maximum speed).
Concept context
Work-energy theorem, potential energy, conservation of energy, collisions.