Knowledge Point 01: Household AC Electricity is Usually 220V, Posing an Electric Shock Risk
The standard voltage of household AC electricity is usually 220V, which is sufficient to cause electric shock accidents and even death. Therefore, when using electricity, we must be extremely careful to avoid direct contact with exposed wires or improper use of electrical appliances.
Detailed Explanation: Household AC electricity is an indispensable energy source in our daily lives, but it is also a potential danger. A voltage of 220V is sufficient to harm the human body, so we must strictly adhere to the safety regulations for using electricity.
When using electrical appliances, ensure that they are properly grounded and avoid using damaged wires or plugs. Additionally, avoid using electrical appliances in damp environments to prevent electric shock accidents.
Knowledge Point 02: Electricity is Classified into Two Categories Based on Electric Shock Risk
Electricity can be divided into two categories based on whether it poses an electric shock risk: electricity without electric shock risk and electricity with electric shock risk. Understanding this is crucial for safe electricity use.
Detailed Explanation: Electricity without electric shock risk, such as that from dry batteries, usually has a low voltage and does not harm the human body. However, electricity with electric shock risk, such as household AC electricity or high-voltage electricity, is highly dangerous.
Therefore, when using electrical appliances, we need to judge whether they pose an electric shock risk based on the voltage level and take corresponding protective measures.
Knowledge Point 03: Avoid Sheltering Under Large Trees During Outdoor Thunderstorms to Prevent Lightning Strikes
When encountering thunderstorms outdoors, one should avoid sheltering under large trees, especially isolated ones, as they are prone to being hit by lightning, posing a threat to humans.
Detailed Explanation: During thunderstorms, the charge distribution in the atmosphere is uneven, easily forming lightning. Due to their height and conductivity, large trees are likely to become targets for lightning discharges.
If a person shelters under a large tree during a thunderstorm, they may be hit by lightning, causing severe injury or even death. Therefore, when encountering thunderstorms outdoors, we should stay away from tall objects such as trees and utility poles and seek shelter in low-lying areas or buildings.
Knowledge Point 04: Bulbs Emit Light When Current Passes Through the Filament
When current passes through the filament inside a bulb, the filament heats up due to resistance and emits light, which is the basic principle of bulb illumination.
Detailed Explanation: The filament inside a bulb is made of a metal with a high resistivity. When current passes through it, the filament heats up to incandescence and emits light.
In this process, electrical energy is converted into light energy and thermal energy. The lighting effect of a bulb depends on factors such as the material, thickness of the filament, and the magnitude of the current.
Therefore, when choosing a bulb, we need to select the appropriate power and type based on actual needs.
