An ice chest at a beach party contains 12 cans of soda at 4.05 °C. Each can of soda has a mass of 0.35 kg and a specific heat ca
pacity of 3800 J/(kg C°). Someone adds a 6.21-kg watermelon at 24.0 °C to the chest. The specific heat capacity of watermelon is nearly the same as that of water. Ignore the specific heat capacity of the chest and determine the final temperature T of the soda and watermelon in degrees Celsius.
If we can approximate the ion channel to be Ohmic, this means that we can apply Ohm's Law to get the voltage of the action potential, as follows:
The definition of electric current, is the rate of change of the charge, i.e., the amount of total charge crossing a given area, perpendicular to the flow of charge carriers, per unit time.
If we know that approximately 90000 single ionized potassium ions travel through the channel during 0.6 mseg, we can find the value of the current.
The charge represented by 90000 single ionized potassium ions, is the same as 90000 positive elementary charges, equal to 1.6*10⁻¹⁹ C each (as the potassium single ionized carries a +1 e charge).
So, total charge is just the product of 90000 by 1.6*10⁻¹⁹ C: