"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 7

Description

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 7

concept

1. The work done by the current per unit time is called electric power, the formula P=W/T.

2. Electric power is equal to the product of voltage and current, the formula is ________.

How to measure electrical power

1. According to P=W/T, measure the electrical power and work time, and calculate the electrical power;

2. According to P = U I, measure the voltage and current, and calculate the electrical power;

3. Measure the electrical power directly with a power meter.

It can be seen that there are many ways to measure electrical power, and different methods use different equipment.

We have to choose the appropriate method according to the conditions. (Only suitable, not best)

In this lesson, you will learn to use a voltmeter and ammeter to measure the electrical power of a small light bulb.

Use voltmeter and ammeter to measure the electric power of small light bulbs

1. Purpose: Measure the rated electric power and actual electric power of small light bulbs

2. Principle P=UI

3. Make a plan

It can be seen from the formula P=UI: To measure the electric power of the small bulb, you need to use a voltmeter to measure the voltage at both ends of the small bulb, and use an ammeter to measure the current in the small bulb at this time.

When the voltage across the small bulb is equal to the rated voltage, the electrical power of the small bulb is called the rated electrical power; under other circumstances, it is usually called the actual electrical power.

In order to adjust the voltage across the small bulb, a sliding rheostat is used.

4. Design circuit

1. Measure the rated electrical power of the small light bulb

At this time, the light bulb's lighting condition is called: normal lighting.

2. Measure the electrical power of small light bulbs at different voltages

①The actual power when it is about one-fifth higher than the rated voltage, contrast brightness (compared with the brightness at rated voltage), actual power compared with rated power.

② When the actual power is lower than the rated voltage, observe the brightness of the small bulb and compare it with the brightness at the rated voltage, and compare the actual power with the rated power.

Analysis Communication

1. The rated power of the small light bulb is _______; ________.

2. When U real > U amount, P real ____P amount; _____.

When U real = U amount, P real ____P amount; ________.

When U real

The brightness of the small bulb is determined by the actual power of the small bulb. The greater the actual power, the brighter the small bulb.

Expand and improve: experimental reflections

(1) The voltmeter pointer is too far out of the scale. What is the reason? How to deal with it?

(2) The deflection angle of the ammeter pointer is too small. What is the reason? How to deal with it?

(3) Why is the meter pointer reverse-biased?

(4) What other problems did you encounter during the experiment? How did you solve it?

Keywords: Electric power teaching courseware, Measuring the electric power of small light bulbs teaching courseware, New People's Education Edition ninth grade physics PPT courseware, Ninth grade physics slide courseware download, Electric power PPT courseware download, Measuring the electric power of small light bulbs PPT courseware download, .ppt format

For more information about the PPT courseware "Electrical Power Measuring the Electric Power of Small Light Bulbs", please click the Electric Power ppt Measuring the Electric Power of Small Light Bulbs ppt tag.

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 9:

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 9 Teaching Objectives 1. Deepen the understanding of electric power. 2. Consolidate the operating skills of ammeters and voltmeters. 3. Experience the difference between rated power and actual power through measurement. 4. Train students to use the measurement formula P=U..

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 8:

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 8 Want to Discuss Commonly used small light bulbs are marked with rated voltage (such as 2.5 V, 3.8 V), but not with rated power. For example, the rated voltage of a small light bulb is 2.5 V. How to measure its rated electrical power? Student...

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 6:

"Measuring the Electric Power of Small Light Bulbs" Electric Power PPT Courseware 6 Rated voltage, rated power 1. Rated voltage Ue is the voltage when the electrical appliance is working normally. 2. Rated power Pe is the power of the electrical appliance when it is working normally (power at rated voltage). Skills: Right...