number of primary or secondary cells arranged in series or parallel formation is
Answers
Answer:
Explanation:
The beginning of cells
Alessandro Volta invented electric battery. It was first named as Voltaic Pile. For his contributions to science, the unit of electric potential is named as Volt. John Frederic Daniell developed Daniell cell. Then George Leclanche invented Wet cell and Dr. Carl Gassner introduced the Dry cell battery. Gaston Plante introduced the first rechargeable battery. It is the lead-acid battery and is again most common application found in cars.
Cell
We know that electrical current is the flow of charged particles. It is the flow of electrons through a circuit.
A collection of two or more cells which are connected in series is called A Battery. A battery is an energy source that converts chemical energy to electrical energy. It is otherwise known as Electrochemical Cell. The energy is stored in the form of chemical energy inside a battery. Batteries give us a convenient source of energy for energizing devices without cables and wires. When it is connected to a circuit it produces electrical energy. A battery consists of two terminals – A Positive and Negative Terminal. The positive terminal is called Cathode and the negative terminal is called Anode. They are also called as Electrodes of a Cell. These electrodes will be dipped in a solution called Electrolyte. It is liquid which is ionic and conducts electricity.
When the battery is about to charge, an external source is connected to it. The anode of the battery is connected to the negative terminal of the source and cathode is connected to the positive terminal of the source. As the external source is connected to the battery, electrons are inserted into the anode. When the cell or battery is connected to the circuit chemical reactions takes place. Thus chemical reactions takes place within the two electrodes. Here oxidation and reduction reactions happens. Then reduction reaction occurs at cathode and oxidation process occurs at anode.
A dry cell
A dry cell
The cathode act as the oxidizing agent by accepting electrons from the negative terminal anode. The anode act as the reducing agent by losing the electrons. Thus due to these chemical reactions an electrical difference occurs between the terminals-anode and cathode. When there is no power the electrolyte prohibits the movement of electrons directly from anode to cathode. This is why we are using an external source or connecting to a circuit. Thus electrons travel from anode to cathode when the circuit is closed. Finally it gives power to the appliance which is connected to it. After a long time when the electrochemical process alters the anode and cathode materials it stop giving out electrons. Then the battery dies.
EMF:
EMF or Electromotive force is defined as the potential difference which is developed between the two terminals of a battery in an open circuit. We know that anode has positive potential (V+) and cathode has negative potential (V-). So emf is the potential difference between the positive terminal anode and negative terminal cathode when there is no current flowing through it. The emf measures the energy which is transferred to the charge carries in the cell or a battery. It is the energy in joules divided by the charge in coulombs. The emf acts as the initiating force for the current to flow.
ε = E/Q, where ε is the electromotive force, E is the energy and Q is the charge.
The emf which is denoted by ε and the equation is given by ε = V+ - (-V-) = V+ + V-. It is measured in volts.
Internal Resistance:
Internal Resistance is the resistance which is present within the battery that resists the current flow when connected to a circuit. Thus, it causes a voltage drop when current flows through it. It is the resistance provided by the electrolyte and electrodes which is present in a cell. So Internal resistance is offered by the electrodes and electrolyte which oppose the current flow inside the cell.
Emf and Internal Resistance Equation:
Consider the circuit given below. The cell can be modified with an emf ε and the internal resistor with resistance r which is connected in series. An external load resistor with