what happens to the thermal conductivity of a wall if its thickness is doubled? give a solid reason.
Zainraza:
plz answere
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Thermal Conductivity:
" The rate of flow of heat across the opposite faces of a metre cube of a substance maintained at a temperature difference of one kelvin is called as Thermal Conductivity of substance[k]"
Q/t=K*A(T1-T2)/L
WHERE Q/T IS RATE OF FLOW HEAT.
Rate of Flow of Heat=Q/t
Rate of Flow of Heat [q/t] depends on :
1. Cross sectional area of solid
Q/t α A --------(1)
Larger the cross sectional area A of solid, larger number of molecules and free electrons on each layer parallel to its cross sectional area and hence greater will be rate of flow of heat through solid.
Thus, If Thickness of wall is doubled,The thermal conductivity becomes double.
" The rate of flow of heat across the opposite faces of a metre cube of a substance maintained at a temperature difference of one kelvin is called as Thermal Conductivity of substance[k]"
Q/t=K*A(T1-T2)/L
WHERE Q/T IS RATE OF FLOW HEAT.
Rate of Flow of Heat=Q/t
Rate of Flow of Heat [q/t] depends on :
1. Cross sectional area of solid
Q/t α A --------(1)
Larger the cross sectional area A of solid, larger number of molecules and free electrons on each layer parallel to its cross sectional area and hence greater will be rate of flow of heat through solid.
Thus, If Thickness of wall is doubled,The thermal conductivity becomes double.
Ma'am, could you please check this answer again, the rate of flow of heat will be doubled, but does thermal conductivity double?
FOURIER'S LAW OF HEAT CONDUCTION SAYS:
q=KAdT/S
where q is heat transfer, K-thermal conductity , dt- temperature gradient , s=material thickness . So thermal conductivity is proportional to thickness , and it predicts the rate of energy loss . in this case heat loss decreases and thermal conductivity increases
hope its clear.
Ok ma'am.
But thermal conductivity is constant for a substance so then how can it change
I am not clear with it
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10
Thermal conductivity will remain same because it is constant for every substance
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