"Measuring Electric Power" Current Work and Electric Power PPT Courseware 3

Description

"Measuring Electric Power" Current Work and Electric Power PPT Courseware 3

1. Import

Ask students to think about two questions.

1. What physical quantity does electrical power represent?

2. What are the calculation methods?

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

Electric power calculation formula

P=W/t P=UI

Want to discuss: Looking back at the experiment of "Measuring the resistance of a small light bulb" in the previous chapter, can you find a way to measure the electrical power of the small light bulb?

According to the formula: P=UI, by measuring the voltage across the small bulb and the current flowing through the bulb, the electrical power can be calculated.

2. Measure the electrical power of small light bulbs

1. Experimental purpose:

Measure the rated and actual power of small light bulbs

2. Experimental principle: P=UI

3. Physical quantities that should be measured: _____ and ______.

4. Experimental equipment:

A small light bulb with a rated voltage of 2.5V, ________, switch, sliding rheostat, ________, ________, and several wires.

think about it

(1) Why is a sliding rheostat added to the experiment?

Answer: In order to continuously change the voltage at both ends of the small bulb to reach a certain value.

(2) How to connect the small light bulb and the sliding rheostat? Why?

Answer: In series, in order to use a sliding rheostat to change the current in the circuit, thereby changing the voltage across the small bulb.

(3) Where should the ammeter and voltmeter be connected respectively?

Answer: The voltmeter should be connected in parallel with the small bulb, and the ammeter should be connected in series with the small bulb.

(4) Where should the slider of the sliding rheostat be placed before closing the switch? Why?

Answer: The position with the largest resistance value serves the purpose of protecting the circuit.

practice

1. In the experiment of measuring the rated power of a small light bulb with a rated voltage of "3.8V", the power supply voltage is 6V; the power of the small light bulb does not exceed 1.5W, then the correct choice of the range of the voltmeter and ammeter is ( )

A. 0~3V 0~0.6A

B. 0~15V 0~0.6A

C. 0~15V 0~3A

D. 0~3V 0~3A

2. In the experiment of measuring the electrical power of a small light bulb (2.5V 0.5A), (1) the power supply should be at least ____ dry batteries,

(2) To measure the rated power of the small light bulb, after closing the switch, the correct operation is ____________________.

(3) The indications of the voltmeter and ammeter during a certain experiment are as shown in the figure, then the actual power of the small light bulb at this time is ______W.

3. The filament of a light bulb is burned out. If you put the broken filaments together, the light bulb will be brighter. How to explain this phenomenon?

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For more information about the "Current Work and Electric Power Measuring Electric Power" PPT courseware, please click the Current Work and Electric Power ppt Measuring Electric Power ppt tag.

"Measuring Electric Power" Current Work and Electric Power PPT Courseware 2:

"Measuring Electric Power" Current Work and Electric Power PPT Courseware 2 Warm review: 1. What is electric power? The work done by electric current in unit time 2. What is the physical meaning of electrical power? Electric power is a physical quantity that expresses the speed of work done by electric current. 3. What are the calculations of electric power?

"Measuring Electric Power" Current Work and Electric Power PPT Courseware:

"Measuring Electric Power" Experimental exploration of current work and electric power PPT courseware: Measuring the electric power of a small light bulb Experimental principle: Use _____ to measure the voltage U at both ends of the small light bulb. Use _____ to measure the current I through the small light bulb. Calculate according to _____ The electrical power of a small light bulb. Experimental circuit:..

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Update Time: 2024-07-25

This template belongs to Physics courseware Shanghai Science Edition Ninth Grade Physics industry PPT template

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