3_Resistance - heat to glow. Why we use a thin wire in a...

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1 Resistance • Resistance • Resistivity Water Analogy • What can be done to a pipe to increase the resistance to flow of water? Decrease the diameter of the pipe • If resistance to the flow of water increases, what happens to the overall current? - Current decreases Relation to Resistance • The same is true for Electricity. • Opposition to motion of charge through a conductor is resistance . • Factors affect resistance through a circuit. – The kind of metal (conductivity). – Length of wire (longer = greater resistance). – Thickness of the wire ( thicker = less resistance). – Temperature (higher = greater resistance). Resistance can cause heat and light • Electrical resistance is friction in the wire. • Measured in Ohms ( Ω ) • Electrical resistance causes warming or enough
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Unformatted text preview: heat to glow. Why we use a thin wire in a light bulb: more resistance, hotter faster. 2 The light bulb Tungsten wire - high resistance causing it to glow white-hot. Also, tungsten doesn't burn up as fast, so lasts longer. Schematic symbol: Resistance and Resistors Wires relatively low resistance. Resistors- designed to have a specific resistance; reduces the amount of current. Schematic symbol: Potentiometer Variable resistor that gives a smooth continuous change in current. Dimmer on a light Speed adjustment on fan. Volume adjustor on TV Resistance and Your Body Dry Skin: 500,000 Wet Skin: 100 Rubber soles of shoes can resist 120V; but wet feet on bathroom floor cannot. 3...
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3_Resistance - heat to glow. Why we use a thin wire in a...

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