Heating & Chemical Effects of Current

Introduction

When an electric current passes through a conductor or an electrolyte, it produces various effects. The most significant effects are the heating effect and the chemical effect of current. The heating effect is observed in electric appliances such as heaters, irons, and bulbs, whereas the chemical effect is used in electroplating, electrolysis, and batteries.

Understanding these effects is crucial for NEET aspirants as they have wide applications in daily life and industries.

Heating Effect of Electric Current

The heating effect of electric current is based on the conversion of electrical energy into heat energy when current flows through a conductor. This is explained by Joule’s Law of Heating, which states that the heat produced in a conductor is directly proportional to:

• The square of the current flowing through it.

• The resistance of the conductor.

• The time for which the current flows.

Applications of Heating Effect of Current

• Electric Heaters and Geysers: The heating coil in these devices resists the current flow, generating heat.

• Electric Iron and Toaster: The metal plates or coils heat up due to resistance.

• Incandescent Bulbs: The filament inside the bulb gets heated due to resistance, producing light.

• Electric Fuses: Fuses melt when excessive current flows, preventing damage to appliances.

• Electric Welding: The heating effect is used to melt metals and join them together.

Factors Affecting the Heating Effect

• Material of the Conductor: High-resistance materials like nichrome generate more heat.

• Amount of Current Flowing: More current leads to greater heat production.

• Time Duration: Longer the current flows, more heat is produced.

Chemical Effect of Electric Current

When an electric current is passed through a liquid (electrolyte), it causes chemical changes. This process is known as electrolysis. The electrolyte dissociates into ions, and chemical reactions occur at the electrodes.

Electrolysis and Its Applications

Electrolysis is widely used in various industries for extracting and refining metals, electroplating, and chemical production.

• Electroplating: A thin layer of a desired metal (like gold or silver) is deposited onto another object. This is used in jewelry, cutlery, and decorative items.

• Purification of Metals: Impure metals like copper and aluminum are purified using electrolysis.

• Production of Chemicals: Electrolysis is used in the production of chlorine, hydrogen, and sodium hydroxide.

• Battery Operation: Chemical effects of current are responsible for charging and discharging batteries in mobile phones, cars, and inverters.

Electrochemical Cells and Batteries

• Primary Cells: Cannot be recharged (e.g., dry cell, Leclanché cell).

• Secondary Cells: Rechargeable cells (e.g., lead-acid battery, lithium-ion battery).

Applications of Chemical Effect of Current

• Electroplating for Corrosion Resistance: Protects iron and steel from rusting.

• Electrolysis in Medicine: Used in electrotherapy for pain relief.

• Electrochemical Sensors: Used in blood glucose meters and breath analyzers.

Conclusion

The heating and chemical effects of current have numerous practical applications in industries, household appliances, and medical fields. Understanding these concepts is essential for solving problems related to electricity and electrochemistry in NEET.