NARAYANKAR NOTES

  Difference Between Galvanic Cell and Electrolytic Cell Sr. No. Galvanic Cell Electrolytic Cell 1 It is a cell that converts chemical energy into electrical energy . It is a cell that converts electrical energy into chemical energy . 2 It works spontaneously, meaning the redox reaction occurs naturally. It works non-spontaneously and requires an external power supply. 3 The anode is negative because it supplies electrons. The anode is positive because it is connected to the positive terminal of the battery. 4 The cathode is positive because it receives electrons. The cathode is negative because it is connected to the negative terminal of the battery. 5 Oxidation occurs at the anode and reduction at the cathode (same as electrolytic cell). Oxidation occurs at the anode and reduction at the cathode (same as galvanic cell). 6 Used to genera...

  Difference Between Oxidation and Reduction Sr. No. Oxidation Reduction  1  Oxidation is the loss of electrons from an atom, ion, or molecule.  Reduction is the gain of electrons by an atom, ion, or molecule.  2  Oxidation increases the positive charge or decreases the negative charge of a species.  Reduction decreases the positive charge or increases the negative charge of a species.  3  It involves an increase in oxidation number .  It involves a decrease in oxidation number .  4  Substance undergoing oxidation acts as a reducing agent .  Substance undergoing reduction acts as an oxidising agent .  5  Example: Zn → Zn²⁺ + 2e⁻ (Zinc loses electrons).  Example: Cu²⁺ + 2e⁻ → Cu (Copper ion gains electrons).  6  Occurs at the anode in both galvanic and el...

  Dry Cell Introduction A dry cell is a type of electrochemical cell that converts chemical energy into electrical energy . It is called "dry" because it uses a paste or gel instead of a liquid electrolyte, making it portable, safe, and easy to use in everyday devices like torches, clocks, and remotes. Construction of a Dry Cell Outer Zinc Container: Acts as the negative electrode (anode) and also serves as the cell’s container. Cathode (Positive Electrode): A carbon rod placed at the center of the cell, surrounded by a mixture of manganese dioxide and carbon powder. Electrolyte Paste: Made of ammonium chloride (NH₄Cl) and zinc chloride (ZnCl₂). It allows ions to move between the electrodes. Depolariser: Manganese dioxide (MnO₂) is used to remove hydrogen formed at the cathode, which helps maintain smooth flow of current. Sealing Cap and Insulation: The top is sealed with wax or plastic to prevent drying of the electrolyte and to ensure safety. ...

  Examples of Energy Transformation Energy transformation means the process by which energy changes from one form to another. This happens in both physical changes (where only the state changes, not the substance itself) and chemical changes (where new substances are formed). 1. Physical Changes In physical changes, energy is usually absorbed or released, but the chemical composition of the substance remains the same. Water to Vapor (Evaporation): Thermal energy (heat) from the surroundings is absorbed by water molecules. This increases their motion and allows them to break free from the liquid surface, transforming into vapor. Ice to Water (Melting): Thermal energy is absorbed by ice, which weakens the bonds holding water molecules in a solid structure. This turns ice (solid) into water (liquid) without changing its chemical nature (still H₂O). 2. Chemical Changes In chemical changes, energy is transformed into completely new forms while creating new substance...

  Energy in Physics Introduction In physics, energy is defined as the capacity or ability to do work. Work means applying a force on an object and making it move in the direction of that force. Without energy, no physical process in the universe can take place. Key Characteristics of Energy Scalar Quantity: Energy has magnitude but no direction. Conserved: Energy cannot be created or destroyed; it can only change from one form to another (Law of Conservation of Energy). Transferable: Energy can move from one object to another, for example, from the Sun to Earth as light and heat. Measurable in Joules: The SI unit of energy is the joule (J) , where 1 joule = work done when a force of 1 newton moves an object 1 metre in the direction of the force. Different Forms of Energy Kinetic Energy: The energy an object has because of its motion. For example, a moving car or flowing river. Potential Energy: The stored energy an object has because of its posit...