"Rheostats" Voltage and Resistance PPT Courseware

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"Rheostats" Voltage and Resistance PPT Courseware

conductors and insulators

Conductor: An object that is good at conducting electricity.

Insulator: An object that is not good at conducting electricity

The charge is almost all bound within the atomic range and there is almost no free charge

There are a large number of free charges in the conductor. Under the action of voltage, the free charges move in a direction to form an electric current, so the conductor can conduct electricity.

resistance

1. Definition: A physical quantity that expresses the obstruction effect of a conductor on current flow.

2.Unit:

(1) International unit: ohm, referred to as ohm, symbol Ω

(2) Commonly used units: kiloohms (KΩ), megaohms (MΩ)

(3) Conversion relationship:

1KΩ=103Ω

1 MΩ=106Ω

3. Resistor symbol:

Explore the factors that determine resistance size

Ask the question: What factors are related to the resistance of a conductor?

Guess assumptions: material, length, cross-sectional area

Designing Experiments: Controlled Variables Method

conduct experiment:

Analysis and demonstration: (1) The resistance of a conductor is related to the material of the conductor.

(2) For conductors of the same material and the same cross-sectional area, the longer the conductor, the greater the resistance.

(3) For conductors of the same material and length, the smaller the cross-sectional area, the greater the resistance.

Communication Assessment:

Further research showed that the resistance of a conductor is also related to temperature. The resistance of most metals increases with temperature. The resistance of a light bulb when it is normally emitting light is much greater than when it is not emitting light.

summary

The resistance of a conductor is a property of the conductor itself and is only related to the material, length, cross-sectional area and temperature of the conductor.

It has nothing to do with the voltage applied across the conductor and the current flowing through the conductor.

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For more information about the PPT courseware "Rheistor Voltage and Resistance", please click on the Rheostat ppt voltage and resistance ppt tags.

"Rheostats" PPT download:

"Rheistor" PPT download Part 1: Knowledge review 1. What physical quantity is resistance? Answer: Resistance is a physical quantity that represents the resistance of a conductor to current; the greater the resistance, the greater the resistance to current. 2. The factors that affect the size of the resistance are...

"Rheostats" PPT courseware:

"Rheistor" PPT courseware part one content: Rheostat 1. Rheostat: Principle of a device used to change the resistance: the size of the resistance changes with the length of the conductor. The maximum resistance value of this sliding varistor is 20, and the maximum current allowed is 2A. ..

"Rheostats" PPT:

"Rheistor" PPT Part One Content: Review Resistance (symbol: R) 1. Concept: The obstruction effect of conductors on current flow. The more resistant a conductor is to the flow of electricity, the greater its resistance. 2. Unit: ohm (ohm) (symbol: ) kiloohm (K), megaohm..

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Update Time: 2024-09-11

This template belongs to Physics courseware Lu Jiao Edition Ninth Grade Physics Volume 1 industry PPT template

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