Every surface radiates, and it does so as the fourth power of its absolute temperature. Drag T and the power readout leaps; drag emissivity or area and it only scales in step. Double the temperature and the power goes up by exactly sixteen.
Radiated power P = σεAT4
523.17 W
450 K · ε 0.90 · 0.25 m²
Net power Pnet = σεA(T4 − Tc4)
429.14 W
Surroundings at 293 K send 94.03 W back, so the plate loses the difference.
Power per unit area P/A = σεT4
2092.69 W/m²
across 0.25 m² of surface
Against a 300 K baseline (T / 300 K)4
5.06x
Press Double T and this plate radiates exactly 16 times as much power.
Temperature T450 K
Emissivity ε0.90
Surface area A0.25 m²
Surroundings Tc293 K
Stefan-Boltzmann constant σ = 5.670374419 × 10−8 W/(m²·K4) — exact by definition, so it is fixed here. Both temperatures are absolute (kelvin).
Try this: read the power, press Double T, read it again — sixteen times. Then double the area instead, and it merely doubles.