Question

A slab of thermal insulator is 200cm square in cross section and 5cm thick.If thermal conductivity is0.50 and temperature difference is 150 what is the heat flow through the slab in 2 days

Answer 1

Answer: 5184 kJ

Step-by-step explanation:

Given

Area of cross-section
`A=200\ cm^2`

thickness of slab
`t=5\ cm`

thermal conductivity
`k=0.5\ W/m-K`

temperature difference
`\Delta T=150\ K`

Heat flow is given by

`\Rightarrow Q=kA(dT)/(dx)\\\Rightarrow Q=0.5* 200* (150)/(5)* 10^(-2)\\\Rightarrow Q=30\ W\ or\ 30\ J/s`

for 2 days time period, it is

`t=2\ days\ or\ 2* 24* 60* 60\ s\\t=1,72,800\ s`

Heat flow in 2 days

`Q=30* 172800=5184000=5184\ kJ`