14. Current Electricity - Students Free Notes

Describe the hazards of household electricity and four safety measures.

Household electricity can present several hazards, including: Electric Shock: When a person comes into direct contact with an electrical source, it can lead to an electric shock, which can cause burns, muscle spasms, or even be fatal in severe cases. Electrical Fires: Faulty wiring, overloading circuits, or electrical appliances with malfunctioning components can overheat and … Read more

What do you mean by short circuit and open circuit? Define live wire, neutral wire, and earth wire in household circuits.

Short Circuit and Open Circuit: Short Circuit: A short circuit occurs when the live wire (also known as the hot wire) comes into direct contact with the neutral wire, or any other conducting material, bypassing the load (such as an appliance or light). This leads to a low-resistance path for the current to flow, which … Read more

How is electricity supplied to houses by the electricity department? How do we distribute it in household circuits?

Electricity is supplied to houses through a well-organized system that involves multiple steps, from generation to distribution. Here’s how it works: 1. Generation of Electricity: Power Stations: Electricity is generated at power stations (such as coal, hydroelectric, nuclear, or renewable energy plants). These plants convert energy sources (like coal, water, or solar energy) into electrical … Read more

What is the function of a galvanometer, ammeter, and voltmeter? How are they connected in circuits?

A galvanometer, ammeter, and voltmeter are all types of instruments used to measure electrical quantities in a circuit. Each has a specific function and is connected in a unique way to the circuit. 1. Galvanometer: Function: A galvanometer is used to detect and measure small amounts of current in a circuit. It can also be … Read more

12. Differentiate between direct current (DC) and alternating current (AC). Define the following terms for AC: (i) Cycle, (ii) Time period, (iii) Frequency.

Difference Between Direct Current (DC) and Alternating Current (AC) Parameter Direct Current (DC) Alternating Current (AC) Direction Flows in one constant direction. Changes direction periodically. Waveform A constant, unidirectional flow of current. The current alternates between positive and negative cycles, forming a sinusoidal (or other periodic) waveform. Voltage Constant voltage. Voltage alternates between positive and … Read more

Define kilowatt-hour (kWh). What is its relation with joule? How can you calculate energy in kWh by a formula?

Kilowatt-Hour (kWh) A kilowatt-hour (kWh) is a unit of energy that is commonly used to measure electrical energy consumption. It represents the amount of energy consumed by a device with a power rating of 1 kilowatt (kW) operating for 1 hour. In simpler terms, 1 kWh is the energy used when a 1,000-watt device runs … Read more

In a circuit, three bulbs are connected in series and in another circuit, three bulbs are connected in parallel. The magnitude of the emf source for both circuits is the same. How can you explain the difference in brightness of bulbs in both circuits?

The brightness of a bulb is determined by the power it dissipates, which depends on the current passing through it and the voltage across it. Power P dissipated by a resistor (or bulb) is given by the formula: P=V2/R​ or alternatively, in terms of current I: P=I2R where: P is the power dissipated (which determines … Read more