### Stefan Boltzmann Calculator :

This Stefan Boltzmann law calculator describes the Area in meter square(m²), Temperature in °C, Radiated power in watts(W), and you get the calculator check it.

### Stefan Boltzmann Formula :

Stefan Boltzmann formula is thermal radiation ΔQ_{(j)} in joule and time Δ t_{(s)} in second is equal to the emissivity ε_{(w/cm2)} in watts per centimeter^{2 } and multiply the Stefan constant value σ_{(w/m2k2)} in watts per meter^{2} per kelvin^{2} and multiply the surface of the system A_{(m2)} in meter^{2} and multiply the temperature T^{4}_{(0c) } in degree celsius. Hence the thermal radiation of the Stefan Boltzmann formula can be written as,

ΔQ_{(j)}/Δ t_{(s)}=ε_{(w/cm2)}*σ_{(w/m2k2)}*A_{(m2)}* T^{4}_{(0c)}

Where,

σ →5.67*10^{-8} W/m^{2} K^{4}

A→ surface are of system

ε → emissivity in w/cm^{2}

σ→ constant in W/m^{2} K^{4}

net rate of radiation ΔQ/Δ t=ε*σ*A(T^{4}_{1} – T^{4}_{2})

### Example:1

Calculate the net radiation rate, Let A=1.6m^{2}? In a person cools by radiation. Suppose a person stands in a room with dark walls at a temperature of 18^{0 } If ε_{stin}=0.71 and temperature of skin is 36^{0}c.

### Answer:

ΔQ/Δ t=ε*σ*A(T^{4}_{1} – T^{4}_{2})

=(1.6)(0.71)(5.67*10^{-8})(36+273)^{4}-(18-273)^{4}

^{=}717 J/s

### Example:2

A person cools by radiation. Suppose a person stands in a room with dark walls at a temperature of 20^{0 } If ε_{stin}=0.81 and temperature of skin is 4 6^{0}c ?

### Answer:

ΔQ/Δ t=ε*σ*A(T^{4}_{1} – T^{4}_{2})

=(2.6)(0.81)(5.67*10^{-8})(46+273)^{4}-(20 +273)^{4}

=7370 J/s