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Today's Physics Lesson - Form 5

Questions posed by students

1.What happens to a current as it passes through a junction that branches into more than one path?

First you must remember the law of conservation of charge. The total rate of flow of charge must remain the same before approaching the junction and after passing through the junction.

                                                    I1

I                   A

                                                                 I2

At the junction A above, the current I is split into I1 and I2. According to the the law of conservation of charge, we write the equation:

                I  =  I1  +  I2

2. What is a point charge?

A point charge is a place with a high concentration of charge, usually at a sharp point, or just at some sharp edges. As such it creates a strong electric field which is capable of ionising the surrounding atmosphere. This attracts ionised particles of the opposite charge from the surrounding air, thus neutralising the higher charge concentration.

3. What is a thermometric property?

There are many measures of temperature changes. The thermometric property refers to the physical characteristic of a thermometric material that responds to changes in temperature. An example is the change in volume of a column of mercury in a mercury-in-glass thermometer. Mercury is used because it is less prone to evaporation which may saturate the entrapped space in a thermometer. Moreover, it does not "wet" the glass, hence improving the readability of its surface.

zhiq/31/03/05

 

 

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