The inner and outer surfaces of a 4-m × 7-m brick wall of thickness 30 cm and thermal conductivity 0.69 w/m-k are maintained at temperatures of 20 °c and 5 °c, respectively. determine the rate of heat transfer through the wall, in w.

Explanation:

As we know that the rate of heat transfer due to temperature difference is given by the formula

here we know that

A = 4 m x 7 m

thickness = 30 cm

temperature difference is given as

now we have

explanation:

newton's third law, for every action there is an equal and opposite reaction.

option number c is the right answer.