Atomic clocks used in GPS satellites rely on the hyperfine transition of ________ atoms for precise timekeeping.
- Hydrogen
- Cesium
- Rubidium
- Strontium
Answer: Cesium
Cesium-133 hyperfine transition (9,192,631,770 Hz) defines the SI second. Atomic clocks enable GPS positioning accuracy (~5-10 m). Next-gen optical clocks (Sr, Yb) promise 100x improvement. [[NCERT Physics Class 11, ISRO Reports]]