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, while the second and fourth have a thickness of 2 cm and a thermal conductivity of 
. The first layer encloses the interior of the refrigerator with a temperature of 
, and the fourth layer is outside, where the temperature is 
. What is the temperature 
in the middle of the third layer?
has an area of 
and a thickness of 0.4 m. A 
surface window is built into the wall. The window allows a heat flow rate of 1.6 W per square meter of the surface at a temperature difference of 1 K. The difference between the indoor and outdoor temperature is 20 K. What is the heat flow rate through the wall with the window? How much heat is lost in one day?
. Calculate the heat flow per square metre of the Earth's surface. What would be the temperature on the Earth's surface if the surface were not cooled or heated further?
(solar constant). What is the temperature of the plate when thermal equilibrium is established? Calculate for the following two cases:
and is heated to a temperature of 
. The ambient temperature is 
. What is the heat flow rate from the stove if it radiates like a black body?
. A container with 1 l of water at a temperature of 
is placed in the freezer. Calculate how much heat the water gives off at the time it cools to the temperature in the freezer. The specific heat capacity of water is 
, the specific heat capacity of ice is 
and the specific heat of fusion of water is 
.
and surface area 
has a thickness of 
. The temperature outside the house is 
and the inside is 
.
appear?
has an area of 
. If the heat flow rate through the wall is 360 W and the temperature of the inside face of the wall is 
, what is the temperature of the outside face of the wall?
. If the wall has a recess of 0.2 m inside it, what should be the thickness of the insulator that will be inserted in the recess in order to prevent heat losses?
and 
respectively).
. It is followed by a 40 cm thick brick with a thermal conductivity of 0.8 
. The pot has a bottom with an area of 
and a thickness of 
. It receives heat from the stove only through the bottom.
and an outside temperature 
. What is the heat flow rate through the wall? Where in the wall are the negative temperatures?
.
. The temperature outside the cylinder is 
. If the water is heated with a 6 kW heater, what must be the thickness of the wall of the container in order to keep the water at a constant temperature at all times?
surface of the wall will be 3 W? The difference between the temperatures of the inner and outer sides of the coated wall is 
. The thermal conductivity of hollow bricks is 0.6 
and that of styrofoam is 0.04 
on the inside and 
on the outside. What is the ratio of the heat loss through the window to that through the wall?
and a 30 cm thick bricks with thermal conductivity 
.
and a temperature of 
. The emissivity of the skin is 0.3. Calculate the power of an electric heater that would replace the adult's radiation.
.
while the aluminum end is immersed in a mixture of water and ice at a temperature of 
. What is the temperature at the junction of the two bars?
. The light bulb is supplied with electricity by 2 W batteries. The air in the container has a temperature of 
before the light bulb is turned on. What will be the air temperature after 30 minutes?
.
