"How fast electric current does work" Current work and electric power PPT courseware 3

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"How fast electric current does work" Current work and electric power PPT courseware 3

The aluminum disc on the electric energy meter in our home sometimes moves slowly, sometimes in a hurry. why?

What does the rotation speed of the aluminum disk have to do with it?

The aluminum disk rotates at different speeds, which means that the electrical appliance consumes electricity at different speeds.

In the same period of time, which one consumes more energy, an electric fan or an air conditioner?

In the same period of time, the greater the electric power of the air conditioner consumes more electrical energy, the faster the turntable of the energy meter rotates.

1. Electric power

1. Concept:

The amount of electrical energy consumed by current per unit time is called electrical power. Represented by the letter "P".

Electric power is a physical quantity that expresses the speed of consuming electrical energy.

2. Calculation formula: P=W/t

3. The unit and physical meaning of electrical power

Unit name: watt (referred to as watt)

Unit symbol: W

Unit conversion: 1 kilowatt = 1000 watts

The electric power of a certain motor when working is 60KW, which means:

The electric motor consumes 60,000 joules of electrical energy per second.

The relationship between electric power P, current I, and voltage U is P=IU

The meaning and unit of the symbol:

P——Power——Watt (W)

U——Voltage——Volt (V)

I——Current——Ampere (A)

Note: When using this formula, only when the units of current and voltage are amperes and volts, the unit of power is watts.

1. Can you tell the difference between kilowatts and kilowatt hours?

Kilowatt is a unit of electrical power

A kilowatt hour is a unit of electrical energy (or electrical work).

2. Can you tell the difference between electrical power and electrical energy (or electrical work)?

Electrical power indicates how quickly an electrical appliance consumes electrical energy.

Electrical energy (or electrical work) represents the amount of electrical energy consumed by electrical appliances

2. Rated voltage and rated power

Think about it:

1. Under what circumstances will this light bulb emit light normally?

2. If this light bulb is connected to a 110V circuit, what will happen to its lighting conditions? If it is connected to a 300V circuit, what will happen to its lighting conditions?

Rated voltage: The voltage when the electrical appliance is working normally is called the rated voltage.

Rated power: The power of an electrical appliance at rated voltage is called rated power.

When U real = U amount, then P real = P amount, and the electrical appliances will work normally.

When U is real and P is real, electrical appliances are easily damaged.

When U is in real-time, P is in real-time, and the electrical appliance cannot work properly.

practice

1. Among the electrical appliances in the following figure, the one with a rated power closest to 1000 W is ()

2. A lamp is marked with "36V 40W". When it is connected to the circuit, the current passing through it is 1A, then the actual power of the lamp will be ( )

A. Less than 40W

B． Greater than 40W

C. equal to 40W

D． Unable to judge

3. Connect two light bulbs L1 and L2 with the same rated voltage in series and connect them to the circuit, as shown in Figure 8. After connecting the circuit, it is found that L1 is brighter, then which of the following judgments is correct ( )

A. The resistance of L1 is smaller than that of L2

B． The rated power of L1 is larger than that of L2

C. When the two lights are working normally, L1 will glow darker.

D． If two lights are connected in parallel to the circuit, L1 will glow brighter.

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"How fast electric current does work" Current work and electric power PPT courseware 2:

"How fast electric current does work" Current work and electric power PPT courseware 2 Knowledge review: What is electric power? What are its two units? What's the conversion relationship? The work done by current is called electrical work; the units include joules and degrees; 1 degree = 1 kilowatt hour, 1 degree = 3.6106 joules..

"How fast or slow the current does work" Current work and electric power PPT courseware:

"How Fast or Slow Electric Current Does Work" Current Work and Electric Power PPT Courseware 1. Definition and Characteristics of Electric Power 1. Meaning: A physical quantity that represents the _______ of current work. 2. Definition: Call ____________________ electrical power. 3. Formula: P=w/t. Commonly used formulas are: P=..

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Update Time: 2024-11-22

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