You can reach a temperature of about 120 °C. To calculate this value, follow these steps:
Calculate the Gay-Lussac's law constant at atmospheric pressure:
k = p₁/T₁ = 0.99 bar/100 °C = 0.0099 bar/°C
Divide the pressure your cooker can reach by k:
T₂ = p₂/k = (0.99 + 0.2) bar/0.0099 bar/°C = 120.2 °C
Notice that you can compute the excess temperature by plugging the overpressure directly in the formula:
ΔT = Δp/k = (0.2) bar/0.0099 bar/°C = 20.2 °C
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