In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?
1. Area of the hole in the lid
2. Temperature of the flame
3. Weight of the lid
Select the correct answer using the code given below:
Explanation
Inside an enclosed pressure cooker, food cooks in boiling liquid and steam. The cooking temperature corresponds to the boiling point of water under pressure, governed by the basic physical law where Pressure equals Force divided by Area (P = F / A):
– The internal pressure limit is set by the downward force of the weight over the discharge vent: Internal Gauge Pressure = Weight of the lid vent / Area of the vent hole.
– 1. Area of the hole in the lid (Correct): Directly determines the pressure threshold maintained inside the vessel before steam releases.
– 3. Weight of the lid/vent weight (Correct): The mass of the pressure regulator weight exerts the gravitational downward force counteracting steam pressure, dictating the maximum vapor pressure and corresponding boiling point.
– 2. Temperature of the flame (Incorrect): Flame intensity dictates the rate of heat transfer (speed at which water boils and steam accumulates), but once operational pressure is achieved, additional heat merely produces excess steam without increasing the steady-state boiling temperature.
Therefore, factors 1 and 3 determine the cooking temperature — Option C.