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ELECTRIC CURRENT




Current and Charge

Current is the rate of flow of charge, and is present due to the passage of charged particles.
The convention for the direction of current is from +ve to -ve. However, because the charge carriers
inside metals are conduction electrons, the electricity flows from ­ve…

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ELECTRIC CURRENT




DEFN P.D: work done / energy transferred per unit charge.

DEFN VOLT: Potential difference across a component is 1 volt when you convert 1 Joule of
energy moving 1 Coulomb of charge through a component.

DEFN EMF: the emf () of a source of electricity is defined as…

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ELECTRIC CURRENT




NB: Area of a conductor with a circular cross-section is d2 or r2
4

For a conductor of length L and uniform cross-sectional area A, its resistance R is:

proportional to L

inversely proportional to A

Therefore, Resistance = constant for the material (resistivity) x length
area

Thus,…

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ELECTRIC CURRENT




The resistance of an LDR depends on light intensity. The greater the light intensity shining on an LDR,
the lower its resistance. This works in exactly the same way as the thermistor, but instead of the
temperature, it's the light intensity.

Diodes only let current flow in one…

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