How much heat will flow Thermodynamics

[hsphysics2]

Homework Statement

How much heat will flow in 30 minutes through a 2m X 2m section of concrete (k= 8.36 x 10^-1 J/s m *C) 20 cm thick if the inside temperature if 21*C and the outside temperature is -10*C?

Homework Equations

Not sure but Q/t= {(kA/L} Tkelvin or Q/t= εσAT^4kelvin

The Attempt at a Solution

I did not attempt the solution because i have no idea what formula to use or how to approach a problem like this

 

[Chestermiller]

Homework Statement

How much heat will flow in 30 minutes through a 2m X 2m section of concrete (k= 8.36 x 10^-1 J/s m *C) 20 cm thick if the inside temperature if 21*C and the outside temperature is -10*C?

Homework Equations

Not sure but Q/t= {(kA/L} Tkelvin or Q/t= εσAT^4kelvin

The Attempt at a Solution

I did not attempt the solution because i have no idea what formula to use or how to approach a problem like this

Your first equation is the one to use, but you should have a ΔT, rather than a Tkelvin. This is a heat conduction problem.