Chapter at a Glance | Physics for JAMB PDF Download

Liquids

Electrolytes and Non-electrolytes

• Electrolytes are substances that can conduct electricity in their aqueous or molten state.
• They dissociate into ions when dissolved or melted, allowing the flow of electric current.
• Examples of electrolytes include acids, bases, and salts.
• Non-electrolytes, on the other hand, do not dissociate into ions and cannot conduct electricity.
• Examples of non-electrolytes include sugar, alcohol, and pure water.

Concept of Electrolysis

• Electrolysis is the process of using electric current to bring about a chemical reaction.
• It occurs in an electrolytic cell consisting of two electrodes (anode and cathode) and an electrolyte solution.
• When a direct current is passed through the electrolyte, positive ions move towards the cathode, and negative ions move towards the anode.
• At the electrodes, reduction (gain of electrons) occurs at the cathode, and oxidation (loss of electrons) occurs at the anode.

Faraday's Laws of Electrolysis

• Faraday's First Law states that the amount of a substance produced or consumed during electrolysis is directly proportional to the quantity of electric charge passed through the electrolyte.
• Faraday's Second Law states that the amounts of different substances produced by the same quantity of electric charge are in the ratio of their respective chemical equivalent weights.

Application of Electrolysis

• Electroplating: It is the process of depositing a layer of metal onto a conductive surface using electrolysis. It is used to improve the appearance, protect against corrosion, and modify the properties of objects.
• Calibration of ammeter: Electrolysis can be used to calibrate an ammeter by passing a known current through a solution and measuring the amount of substance produced.

Gases

Discharge through Gases

• Discharge through gases refers to the flow of electric current through a gas.
• Gases can conduct electricity under specific conditions, such as low pressure or when ionized.
• When a high voltage is applied across a gaseous medium, it can undergo electrical breakdown and become ionized, allowing current to flow.
• This leads to the formation of a plasma, which consists of positive ions, negative ions, and free electrons.

Application of Conduction of Electricity through Gases

• Neon signs and fluorescent lamps: These lighting devices utilize the conduction of electricity through gases to produce light.
• Gas discharge tubes: They are used in physics experiments to study the behavior of charged particles in electric and magnetic fields.
• Lightning: The phenomenon of lightning is a natural example of electricity conducted through gases (air) due to a potential difference between the cloud and the ground.