100 W incandescent bulb (10% visible efficiency) · 5 W walkie-talkie at 462 MHz
100 W incandescent bulb
10% visible efficiency → 10 W as light
visible photons / second3.2 × 10¹⁹
wavelength550 nm
frequency545 THz
useful power10 W
E / photon3.61 × 10⁻¹⁹ J
eV / photon2.25 eV
90 W lost as infrared / heat
5 W walkie-talkie
462 MHz UHF · FRS/GMRS · all 5 W radiated
radio photons / second1.64 × 10²⁸
wavelength~65 cm
frequency462 MHz
useful power5 W
E / photon3.06 × 10⁻²⁸ J
eV / photon1.9 μeV
Photon clouds — dot density represents relative photon count (log-compressed; true ratio 5 × 10⁸ : 1)
Bulb · 3.2 × 10¹⁹ photons/s
Walkie-talkie · 1.64 × 10²⁸ photons/s
5 × 10⁸×
The walkie-talkie emits 500 million times more photons/sec than the bulb's visible output.
Each radio photon carries 1.18 billion times less energy (1.9 μeV vs. 2.25 eV).
Photon flux — log-compressed scale
Bulb (visible)
3.2 × 10¹⁹ /s
Walkie-talkie
1.64 × 10²⁸ /s
† true linear ratio 5 × 10⁸ : 1 · bars log-compressed for legibility