"Electric Power" Electric Power and Electric Power PPT Courseware 3

Description

"Electric Power" Electric Power and Electric Power PPT Courseware 3

teaching objectives

1. Understand the concepts and formulas of electrical power, and know the units of electrical power.

2. Understand the concept of rated power and be able to distinguish between rated power and actual power.

3. Cultivate our ability to study problems through observation experiments and our ability to conduct comparative analysis.

question? When current passes through the motor of a washing machine, it does 180,000 J of work when it is powered on for half an hour; when it passes through the motor of a public tram, it does 120,000 J of work when it is powered on for 2 seconds.

Question: ①Which motor does more work when the current passes through it? (Through the washing machine motor) ②Which motor does the work faster through which the current passes?

How to compare the size of electrical power?

1. In the same period of time, electrical appliances that consume a lot of electric energy consume faster and have greater electric power.

2. Electrical appliances that consume the same electric energy and are used for a short time consume electric energy quickly and have high electric power.

3. A and B are dual-purpose electrical appliances. A consumes 10 joules of electrical energy in 5 seconds, and B consumes 9 joules of electrical energy in 3 seconds. Which one has the greater electrical power?

Electric power

Physical meaning: The concept of electrical power is introduced in order to express the speed at which electrical appliances consume electrical energy.

Definition: The electrical energy consumed by electrical appliances per unit time.

Formula: P=w/t

Units: In the SI unit:

The unit of electrical energy is Joule (symbol J)

The unit of time is seconds (symbol s)

The unit of electrical power is watt (w) (symbol J/s)

1kw=103w

2. The origin of kilowatt-hour and the formula of electric power

1. The formula of electric power W=P t

In the formula, the units of W, P, and T are still joules, watts, and seconds.

1 joule=1 watt*s (1J=1W*s)

2. If the units of P and t are kilowatts and hours respectively, then after multiplying them, you will get another unit of electrical power - kilowatt hours (degree).

1 kilowatt hour = 1 kilowatt * hour

Common electrical power values

Air conditioner: about 1000W Vacuum cleaner: about 800W

Hair dryer: about 500W TV: about 200W

Range hood: about 140W Refrigerator: about 100W

Flashlight: about 0.5W Calculator: about 0.5mW

Electronic watch: about 0.01mW

The electric power of the air conditioner is greater than that of the TV. Does this mean that the air conditioner must consume more power or faster than the TV?

2. The difference and connection between electric power and electric power.

Electrical work refers to the work done by the current, and it can also be expressed as the amount of electrical energy consumed in the circuit.

Electrical power is equal to the ratio of electrical work to the time used, and is a physical quantity that indicates how quickly electrical energy is consumed.

The size of electrical power is not only related to the amount of work done by the current, but also related to the time it takes to do the work.

3. How to measure electrical power

1. 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.

Rated voltage and rated power

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.

The brightness of the bulb depends on the actual wattage of the bulb.

Notice

1. The speed of consuming electric energy and the amount of electric energy consumed represent different meanings.

2. Kilowatt-hour and kilowatt are two different units.

3. The actual power of electrical appliances is not necessarily equal to the rated power.

Operation

Practical part:

Collect the instructions for various electrical appliances in your home and check their rated voltage and power values; observe the voltage regulator and energy meter; use W = Pt to find out the monthly electrical energy consumed by your home, and calculate how much the electricity bill is.

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For more information about the "Electrical Power, Electrical Power and Electrical Power" PPT courseware, please click on the Electrical Power ppt Electrical Power and Electrical Power ppt tab.

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Update Time: 2024-11-13

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