5.1 Electrical potential difference, current and resistance
✔Battery
∙It converts chemical energy to electrical potential energy.
✔Potential Energy
∙ It is the amount of work done per unit charge.
∙The potential difference across a resistance is the amount of electrical energy converted to heat, per unit charge.
∙Unit: volt (a scalar quantity).
✔ Charge
∙there are 2 types of charges (+ and -) Unit: coulomb ©
✔ Water analogy:
∙Think of p.d. as the water pump(pressure), resistance of the pipe size, and the current as the rate.
∙It converts chemical energy to electrical potential energy.
✔Potential Energy
∙ It is the amount of work done per unit charge.
∙The potential difference across a resistance is the amount of electrical energy converted to heat, per unit charge.
∙Unit: volt (a scalar quantity).
✔ Charge
∙there are 2 types of charges (+ and -) Unit: coulomb ©
✔ Water analogy:
∙Think of p.d. as the water pump(pressure), resistance of the pipe size, and the current as the rate.
✔ Current
∙ It's the flow of charge.
∙It flows form + to -, while electrons flow from - to +.
✔ Conductor:
∙The material allows charge to pass.
∙All metals are good conductors of electricity, but plastics are insulators.
✔ Resistance
∙Resistance depends on the six and material of the conductor.
∙Resistance is related to: cross-sectional area (A), length (L) and the material.
∙R=ƿ(L/A) ƿ: the constant of proportionality of resistivity.
∙The free electrons give the metal atoms energy while flowing.
✔ Ohm's Law
∙Current flowing through an ohmic conductor is directly proportional to the potential difference across it.
∙ V=IR V: The p.d. across a conductor. I: the current flowing through it
✔ Ohmic and non-ohmic conductor
∙Non-phmic conductor doesn't obey Ohm's Law (for example: light bulb)
∙Ohmic conductor obey Ohm's Law.
∙ It's the flow of charge.
∙It flows form + to -, while electrons flow from - to +.
✔ Conductor:
∙The material allows charge to pass.
∙All metals are good conductors of electricity, but plastics are insulators.
✔ Resistance
∙Resistance depends on the six and material of the conductor.
∙Resistance is related to: cross-sectional area (A), length (L) and the material.
∙R=ƿ(L/A) ƿ: the constant of proportionality of resistivity.
∙The free electrons give the metal atoms energy while flowing.
✔ Ohm's Law
∙Current flowing through an ohmic conductor is directly proportional to the potential difference across it.
∙ V=IR V: The p.d. across a conductor. I: the current flowing through it
✔ Ohmic and non-ohmic conductor
∙Non-phmic conductor doesn't obey Ohm's Law (for example: light bulb)
∙Ohmic conductor obey Ohm's Law.