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Given:
Thickness of the container : x = 1 cm = 0.01 m
Thermal conductivity of the sheet : K= 0.025 J s^–1m^–1°C^–1
Temperature of the liquid nitrogen: T₁ = 80 K
Area of the container : A = 0.8 m²
Temperature of the atmosphere : T₂ = 300 K
Formula used:
Rate of amount of heat flowing is given as:

Here, Δθ is the amount of heat transferred, ΔT is the temperature difference, K is the thermal conductivity of the material, A is the area of cross section of the material and x is the thickness of the material.
Here, ΔT = T₂- T₁ = 220 K
Substituting the values we get,


Hence, the rate of heat flow from the atmosphere to the liquid nitrogen is 440 J/s.