- Let S Assume That You Are Experimenting With A Cooker Hob At Home In The Dormitory Without A Saucepan Or Similar On Top 1 (18.33 KiB) Viewed 36 times
• Electric power applied to the plate: P (t) [W]
• Plate temperature (assumed to be evenly distributed in the plate): T (t) [° C]
• Ambient temperature in the kitchen: Empty (t) [° C]
• Mass of plate: m = = 0.5 [kg]
• Specific heat capacity of the hob: cp [J / (kg ° C)] Specific heat transfer number plate / air: h = 20 [J / (s m² ° C)]
• Area for heat transfer plate / air: A = 0.1 [m²]
a) Check in the formula collection from physics or wikipedia what heat capacity cp steel has. Be careful when naming this value.
b) Set up an energy balance for the hob
c) Make sensible assumptions and then find the differential equation that describes the temperature in the plate.
d) Assume that P (t) 100W, the temperature in the plate 60 ° C and the ambient temperature 20 ° C. Show = that the value of the derivative becomes dr (t) = 0.087. What does this value say about? dt
e) Then suppose you turn the 200W hob? What temperature will the hob finally get (stationary temperature)?
f) Which physical parameters do not affect the stationary temperature? Explain in your own words why this makes sense from a physical point of view. Do these parameters affect other properties of the process?
ROMMELSBACHER SOSTEN