Question

At which temperature does the motion of atoms and molecules stop?

0°C
0 C
0°K
0 K

Answer 1

0 K

That is absolute zero (0 kelvin = −273.15 °C), the temperature at which classical thermal motion would cease. Note however:
- The correct notation is "0 K" (no degree symbol).
- Quantum mechanics predicts residual zero‑point motion, and the third law of thermodynamics says you cannot reach exact absolute zero in practice.