Answer:
The concept of zero net current in toroid occurs when we try to determine magnetic field induction outside toroid.
to determine magnetic field outside toroid, we consider a circular loop outside toroid as shown in figure.
to get the net enclosed current inside the loop, let us consider the crosssection AA' in toroid as shown in figure
as we see the crosssection AA' part of figure, we see that currents in the winding are in opposition directions at near to the loop
and far away from loop. Hence the concept of net current zero occurs in toroid when we try to determine
magnetic field induction outside toroid.
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Duracell batteries are an example of an electrochemical cell that is powered between the reaction of Magnesium and Zinc, occurring in basic conditions (alkaline battery). This type of reaction has a precise output of 1.5 volts, and looks like this:
Zn + 2MnO2 ➡️ ZnO + Mn2O3
It’s not rechargeable.
Golf Cart Batteries are an example of an electrochemical cell that is powered by the reaction between Lead and Sulfuric Acid (Lead-Acid battery). This type of reaction occurs on larger scales than an alkaline battery, and thus can generate a variety of powers depending on how many instruments are present within the battery. The reaction looks like this:
PbO2 + Pb + 2H2SO4 ➡️ 2PbSO4 + H2O
This is a rechargeable cell, but is rather prone to discharging by the environment and surroundings of the battery.
Answer:0 J
Explanation:
Given
For first step
change in internal Energy of the system is 
Work done on the system 
For second step
change in internal Energy of the system is 
Work done on the system 
Work done on the system is considered as Positive and vice-versa.
and from first law of thermodynamics

for first step


overall heat added
For overall Process Heat added is 0 J