3. Earth's surface heat flow I provide an estimate of the...

3. Earth's surface heat flow I provide an estimate of the mean surface heat flux at Earth's surface. Using this value and any assumptions you think appropriate, estimate the total flow of heat across Earth's surface. Express your answer in Joule/yr.

Transcript

00:01 Hello everyone here in this portion we are given that there is a plate which is surrounded by the ambient temperature taken as ta and it is equal 20 degrees celsius the surface temperature of the plate ts is equal to 50 degrees celsius so if we convert them to kelvin the ambient temperature will be equal to 293 kelvin and the surface temperature will be equal to 323 kelvin we're given that the emissivity of the plate epsilon is equal to 0 .8 the state difference constant sigma is equal to 5 .67 multiplied by 10 to the bar minus 8 watt per meter square per kelvin to the bar 4 the convective heat transfer coefficient h is given as 6 watt per meters per kelvin we have to find out the heat flux from the plate the heat flux is given by total heat dissipated divided by the area of the plate this heat flux will be due to convection and radiation so we have to add up both the heat fluxes we'll have heat flux u is equal to the heat due to convection divided by the area plus the heat due to radiation divided by area now let us solve this equation the heat flux is equal to the convective heat transfer coefficient multiplied by the area multiplied by the surface temperature minus the ambient temperature divided by the area a plus the heat dissipated due to radiation given by the stiffness constant sigma multiplied by emissivity epsilon multiplied by area multiplied by t s to the power 4 minus t a to the bar 4 divided by area we can observe that in both the terms the area gets cancelled out in the numerary and denominator.

02:09 So let us now put the values.

02:11 8 flux will be equal to 6 multiplied by 323 minus 293 plus 5 .67 multiplied by 10 to the part minus 8 multiplied by 0 .8 multiplied by 323 to the power 4 minus 293 to the power 4.

02:34 On solving this we'll get the value of which comes up to be equal to 339 .42 and the unit is watt per meter square...

Question

3. Earth's surface heat flow I provide an estimate of the mean surface heat flux at Earth's surface. Using this value and any assumptions you think appropriate, estimate the total flow of heat across Earth's surface. Express your answer in Joule/yr.

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