A pot of water is boiling under one atmosphere of pressure. Assume that heat enters the pot only through its bottom, which is copper and rests on a heating element. In two minutes, the mass of water boiled away is m = 4.5 kg. The radius of the pot bottom is R = 6.5 cm and the thickness is L = 2.0 mm. What is the temperature of the heating element in contact with the pot?

Respuesta :

Explanation:

It is given that,

Mass of boiled water, m = 4.5 kg

Radius of the pot bottom, r = 6.5 cm = 0.065 m

Thickness of the pot, t = 2 mm = 0.002 m

We need to find the temperature of the heating element in contact with the pot.

Heat transferred is from pot to water is given by :

[tex]H=\dfrac{kA(T_2-T_1)}{l}[/tex]

[tex]\dfrac{Q}{t}=\dfrac{kA(T_2-T_1)}{l}[/tex]

T₁ is the boiling temperature of water, T₁ = 100⁰ C

[tex]T_2=\dfrac{Q}{kAt}+T_1[/tex], q = m L, L is the latent heat of vaporization

[tex]T_2=\dfrac{mL}{kAt}+T_1[/tex],

k is the thermal conductivity of water, [tex]k=390\ Jm^{-1}s^{-1}(^oC)^{-1}[/tex]

[tex]L=2.26\times 10^6\ Ā Jkg^{-1}[/tex]

[tex]T_2=\dfrac{4.5\times 2.26\times 10^6}{390\times \pi\times (0.065)^2\times 120}+100[/tex]

[tex]T_2=1737.18\ ^oC[/tex]

Hence, this is the required solution.