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Mechanical Properties Of Fluids

Question
CBSEENPH11020557

A slab of stone of area of 0.36 m2 and thickness 0.1 m is exposed on the lower surface to steam at 100oC. A block of ice at 0o C rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is
(Given latent heat of fusion of ice = 3.36 x 105 J Kg-1)

  • 1.24 J/m/s/oC

  • 1.29 J/m/soC

  • 2.05 J/m/so C

  • 1.02 J/m/soC

Solution

A.

1.24 J/m/s/oC

δQ over δt space equals space fraction numerator K A over denominator L end fraction left parenthesis T subscript 1 minus T subscript 2 right parenthesis
Q space equals fraction numerator K A over denominator L end fraction space left parenthesis T subscript 1 minus T subscript 2 right parenthesis t
Q space equals m L subscript f
fraction numerator K A over denominator L end fraction left parenthesis T subscript 1 minus T subscript 2 right parenthesis space t space equals m L subscript f
K space equals fraction numerator m L subscript f L over denominator A left parenthesis T subscript 1 minus T subscript 2 right parenthesis t end fraction
K equals fraction numerator 4.8 space x 3.36 space x space 10 to the power of 5 space x 0.1 over denominator 0.36 space x space 100 space x space 3600 end fraction
space equals space fraction numerator 4.8 space x space 3.36 over denominator 0.36 space x space 36 end fraction
space equals space 1.24 space J divided by m divided by s divided by C presuperscript o