One reason is that when you have been out in the cold, your hands feet and exposed features of your face will take time to recover as the blood circulation improves and supplied warm blood to capillaries. So the relatively warm room you enter will not immediately feel warm until the blood has regained its normal circulation. Other factors are that windows are cooled from the outside and condensation forms on the inside because of moisture in the air. For this condensation to evaporate requires heat, which will be extracted from the room and the air near the windows will be cooled. The cold air will descend and form a draught at floor level and this will tend to make the room cooler.
By definition, Ampere is a unit of current which is a measure of the amount of charge passing through a point in a circuit per unit of time, with an equivalent charge of 1.602 x 10^(-19) Coulomb per electron. To determine the number of electrons passing through the heater, we use the definition of the current. We calculate as follows:
13.5 A = 13.5 C per second
Charge = 13.5 C/s (10 min) ( 60 s / 1 min)
Charge = 8100 C
Number of electrons = 8100 C / 1.602 x 10^(-19) C per electron
Number of electrons = 5.1 x 10^22 electrons
Therefore, there are 5.1 x10^22 electrons that assed through the heater for 10 minutes.
