Types of Electric Cells and Batteries

Answer is C.

When a primary cell is used, chemical reactions in the battery use up the chemicals that generate the power; when they are gone, the battery stops producing electricity and is useless. In contrast, in a secondary cell, the reaction can be reversed by running a current into the cell with a battery charger to recharge it, regenerating the chemical reactants. 
The types of cells mentioned in option A and option are correct.
Hence, option C is correct.

When dissolved in fluid, salts tend to break apart into their component ions, creating an electrically-conductive solution. Common salt is one such salt. common salt is  $ NaCl$ which gives $Na^+$ and $Cl^-$.

the Daniel cell is a type of electrochemical cell invented in 1836. it is consisted of a copper pot filled with a copper sulfate solution , in which was immersed an unglazed earthenware container filled with sulfuric acid and a zinc electrode. Daniel cell is also called Zn-Cu cell and has constant e.m.f of 1.08 volts.

A depolarizer in electrochemistry is a synonym of electroactive substance, i.e., a substance which changes its oxidation state, or partakes in a formation or breaking of chemical bonds, in a charge-transfer step of an electrochemical reaction. In the cells, the term "depolarizer" has been used to denote a substance used in a primary cell to prevent buildup of hydrogen gas bubbles.

By convention, current is assumed to travel from positive to negative direction. The electrons travel from negative to positive. The direction of current is not the same as direction of flow of electrons; they are opposite.

The ideal qualities of standard cells as follows:
(1) The cells must be constructed from high purity materials and be reproducible.
(2) Except when current is flowing there should be no chemical reaction taking place in the cell.
(3) When the cell is thermally cycled it must give the same emf at a given temperature regardless of its thermal history.
(4) When a current is passed through the cell, its emf may change, but it must recover rapdidly and completely on cessation of the current.

(1) to (4) above represent an ideal qualities which only the Weston Standard cell approaches. The Weston Standard cell is constructed with the basic materials- mercury, cadmium, sulfuric acid, and water- are all purified by distillation, starting with the purest materials available. Hence out of given cells cadmium cell is the standard cell.

Alarm clock uses Dry Cell. Rest of the components work on power supply.

When the ends of the metal wire are not connected to a battery, no electric field is produced inside the wire. Thus no force acts on the electrons in the wire. So the electrons collide with each other and move in random directions.

Nickel cadmium cells are used in portable machines that run on electricity. It is rechargeable.

Lithium cell has a negative plate of lithium iron phosphate and a positive plate of carbon. It is also called as button cell.

Electrons are termed as negative charged particles. Thus when electrons move from negative electrode to positive electrode, we say that negative particles move from negative electrode to positive electrode. On the other hand, the positive charges get attracted towards the negative electrode, thus they move from positive electrode to negative electrode.

Dry cells (Leclanche cells) are portable power sources commonly used in low-drain devices like torches, toys, and remote controls.

A voltaic cell is an electrochemical cell that produces electrical energy. In voltaic cell there is an anode where oxidation occurs and a cathode where reduction occurs. So, it produces current and thus emf is produced in voltaic cells.

It is a common misconception that battery or cell delivers charge but this is not true at all.The battery as a whole is electrically neutral and its only job is to provide electrical energy.This is usually done using conversion of chemical energy to electric energy.

According to the Maximum Power Transfer Theorem, the power delivered to an external load is maximized when the load resistance equals the internal resistance of the source. This is derived by setting the derivative of power with respect to R to zero.

The terminal voltage V is given by V = E - Ir, where I = V/r_ext. Substituting I, we get V = E - (V/r_ext) * r_int. Rearranging for r_int gives r_int = (E - V) * r_ext / V. The provided options use 'r' as the external resistance.

Local Action is the tendency for the chemically active components of a cell to react with each other, and so become exhausted even when no current is being drawn from the cell. Local action has the effect of reducing the 'shelf-life' of the cell - it uses up its chemical reserves and becomes exhausted even when not being used.

Equivalent resistance of parallel combination         $\dfrac{1}{R _{eq}}  = \dfrac{1}{R _1}+\dfrac{1}{R _2} + .......$

A battery depolarizer takes up electrons during discharge of the cell and thus it is always an oxidizing agent. The term depolarizer has been used to denote a substance used in primary cell to prevent build up of hydrogen gas bubbles. Manganese dioxide is used as depolarizer in Leclanche cell and dry cell.

Battery is the source of potential difference and wire is a conductor but can't be a perfect conductor. It has some resistance in which voltage gets dropped. As resistance of wire is much smaller so it will be large amount of current through battery and battery will get discharged much sooner.the chemical energy stored get used up very fast.

The electrochemical equivalent (Z) is related to equivalent weight (E) by the formula Z = E / F, where F is Faraday's constant (approximately 96500 C/mol). E = Z * F = 0.0006735 * 96500 = 64.99, which rounds to 65.

We know that the current flows from positive electrode to negative electrode in a cell. The direction of electrons is always opposite to the direction of the current. Thus, the electrons move from negative electrode to positive electrode.  

The e.m.f of a Daniel cell always remains constant and is equal to $1.08$ volts.

When an external circuit is connected across the cell, electrons flow from negative electrode to positive electrode(current flows opposite to this) in the external circuit. Inside the cell, negatively charged ions are attracted to negative electrode because it is depleted of electrons. Similarly, inside the cell, positively charged ions are attracted to positive electrode. 

A common dry cell is zinc-carbon cell with a normal voltage of 1.5 V , same as the alkaline cell.

A battery converts chemical energy into electrical energy.

Dry cell being primary cell, cannot be recharged.
Acids cell are used as car batteries.
The nickel-iron battery (Ni-Fe battery)( also called Edison Cell)  is a rechargable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. It is a very robust battery which is tolerant of abuse, (overcharge, overdischarge, and short-circuiting) and can have very long life even if so treated.

The battery made by Volta is credited as the first electrochemical cell. It consists of two electrodes: one made of zinc, the other of copper. The electrolyte is either sulfuric acid mixed with water or a form of saltwater brine.

The chemical action that occurs in the cell while the current is flowing causes hydrogen bubbles to form on the surface of the anode. This action is called POLARIZATION. Some hydrogen bubbles rise to the surface of the electrolyte and escape into the air, some remain on the surface of the anode. If enough bubbles remain around the anode, the bubbles form a barrier that increases internal resistance. When the internal resistance of the cell increases, the output current is decreased and the voltage of the cell also decreases.

Voltaic cell has a lot of polarization due to ongoing reactions.Daniell cell is an improvement on the voltaic cell using two electrolytes and solves the problem of polarisation.

The charging of all secondary batteries are based on conversion of electric energy to chemical potential energy with the user of battery charger. The negative terminal of the cell has to be connected to the negative terminal of the voltage source and the positive terminal of the voltage source with the positive terminal of the battery. Further, the voltage output of the source must be higher than that of the battery, but not much higher: the greater the difference between the power source and the battery's voltage capacity, the faster the charging process, but also the greater the risk of overcharging and damaging the battery.

The cell EMF is E_cell = E_cathode - E_anode. Given E_cell = 2.7 V and E_copper = +0.34 V (cathode), then 2.7 = 0.34 - E_magnesium. Solving for E_magnesium gives 0.34 - 2.7 = -2.36 V.