"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware 3

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"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware 3

1. Start by understanding the electrical nameplate

Rated voltage 220V

Rated frequency 50Hz

Rated power 1000kW

What does "220–25" on the nameplate mean?

Rated voltage refers to the voltage at which electrical appliances or electrical instruments operate normally.

Power refers to the power of electrical appliances when they operate normally at rated voltage.

2. Electric power

Think about it: If two light bulbs labeled "220V 15W" and "220V 100W" are connected to a household circuit at the same time, which one will be brighter?

1. The concept of electrical power

In physics, the electrical work done by electrical appliances per unit time is called electrical power.

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

2. Electric power calculation formula

P = W/t W=UIt

P=UI

3. Unit of electrical power

Watt (W) (J/s) kilowatt (kW)

1kW=1000W

3. Explore what factors are related to the electric power of the light bulb

1. When the currents are the same:

Conclusion: When the current is the same, the greater the voltage, the greater the electrical power.

2. When the voltages are the same:

Conclusion: When the voltage is the same, the greater the current, the greater the electrical power.

Experiments show: P=UI Unit: W

Example 1. As shown in the figure, the voltage across the small light bulb is 6V, and the current passing through it is 2A. What is the electric power of the small light bulb at this time?

Solution: According to P=UI

P=UI=6V×2A=12W

If the power supply voltage is 6V, how many related physical quantities can be found?

Example 2. An electric lamp is connected to a circuit with a voltage of 220V. The current flowing through the lamp is 68mA. How many watts does this bulb have? If the electricity is energized for a total of 100 hours in a month, how much work is done by the current?

Solution: P=UI=220V×0.068A=15W

W=Pt =15W×3.6×105s=5.4×106J

Or W=Pt=0.015kW×100h=1.5kW·h

=1.5kWh

Consolidation exercises:

1. Electrical work: When ______ can be converted into other forms of energy, we say that electrical work has been done, which is represented by the letter symbol ____, and the international unit is ________. The commonly used unit in life is ______, 1kW·h=________J.

2. Electrical function can be measured using __________.

3. Electric power: The physical meaning of electric power is the physical quantity that represents _______; large electric power means that the current does work ________.

The definition of electric power is: the work done by the current in __________ is called electric power, which is represented by the letter ____. Its main unit is _____, and the commonly used units are _________. The conversion relationship is _____________.

4. The calculation formula of electric power: ______ and ______.

5. Calculate the electric energy consumed by electrical appliances (electrical work done by current) using the formulas W=_______ and W= ________

6. Rated voltage: The voltage of the electrical appliance ________ is called the rated voltage, and the voltage value marked on the electrical appliance is ________.

Summary

1. Let’s start with the nameplate of electrical appliances

2. Electric power

1. Electric power is a physical quantity that describes how quickly an electric current does work.

2. Electric power calculation formula: P=W/t

3. Unit of electrical power

The main unit is watt, referred to as watt, represented by the symbol W

Other units 1kW=1000W 1W=1000mW

3. Explore the factors related to the power of small light bulbs

1. When the current is the same, the greater the voltage, the greater the electrical power.

When the voltage is the same, the greater the current, the greater the electrical power.

2. Experiments show: P=UI

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"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware 2:

"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware 2 Teaching Objectives 1. Understand electric power with examples and know the units of electric power. 2. Know the relationship between electric power, current and voltage, and be able to apply formulas for simple calculations. Detection Preview 1: Understand electrical power with examples,...

"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware:

"Understanding Electric Power" Electric Energy and Electric Power PPT Courseware [Learning Objectives] 1. Understand electrical power with examples and know the units of electrical power. 2. Know the relationship between electric power, current and voltage, and be able to use the formula of electric power to perform simple calculations. 3. Experience research...

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Update Time: 2024-10-31

This template belongs to Physics courseware Guangdong and Shanghai Edition Ninth Grade Physics Volume 1 industry PPT template

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