350 likes | 456 Vues
4.2 Potential difference ( pd ) and power. Potential Difference: * is defined as the work done (or energy transfer) per unit charge. V (Volt) = W (work done, J) Q (charge, C). +. B.
E N D
4.2 Potential difference ( pd ) and power Potential Difference: * is defined as the work done (or energy transfer) per unit charge V (Volt) = W (work done, J) Q (charge, C) + B If 1J of work is done in moving 1 C of positive charge from A to B then the Pd is 1V + A 1V = 1 J / C
4.2 Potential difference ( pd ) and power Potential Difference: * is defined as the work done (or energy transfer) per unit charge V (Volt) = W (work done, J) Q (charge, C) + B If 1J of work is done in moving 1 C of positive charge from A to B then the Pd is 1V + A 1V = 1 J / C
4.2 Potential difference ( pd ) and power Potential Difference: * is defined as the work done (or energy transfer) per unit charge V (Volt) = W (work done, J) Q (charge, C) + B If 1J of work is done in moving 1 C of positive charge from A to B then the Pd is 1V + A 1V = 1 J / C
4.2 Potential difference ( pd ) and power Potential Difference: * is defined as the work done (or energy transfer) per unit charge V (Volt) = W (work done, J) Q (charge, C) + B If 1J of work is done in moving 1 C of positive charge from A to B then the Pd is 1V + A 1V = 1 J / C
4.2 Potential difference ( pd ) and power Potential Difference: * is defined as the work done (or energy transfer) per unit charge V (Volt) = W (work done, J) Q (charge, C) + B If 1J of work is done in moving 1 C of positive charge from A to B then the Pd is 1V + A 1V = 1 J / C
Voltage or pd: * is electrical pressure * causes current to flow * is measured in Volts (V) with a voltmeter in parallel 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V V 1.5 V
Voltage or pd: * is electrical pressure * causes current to flow * is measured in Volts (V) with a voltmeter in parallel 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V V 1.5 V
Voltage or pd: * is electrical pressure * causes current to flow * is measured in Volts (V) with a voltmeter in parallel 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V 1.5 V V 1.5 V
Voltages in series circuits The cell gives electrical potential energy to each electron – even when not connected - J J J - J * Work is done by an electron when passing through a component. * Some of the electron’s electrical potential energy is transferred to heat and light. * The work done per coulomb of charge is called the potential difference across the component
Voltages in series circuits The cell gives electrical potential energy to each electron – even when not connected - J J J - J * Work is done by an electron when passing through a component. * Some of the electron’s electrical potential energy is transferred to heat and light. * The work done per coulomb of charge is called the potential difference across the component
Voltages in series circuits The cell gives electrical potential energy to each electron – even when not connected - J J J - J * Work is done by an electron when passing through a component. * Some of the electron’s electrical potential energy is transferred to heat and light. * The work done per coulomb of charge is called the potential difference across the component
Voltages in series circuits 1.5 V V V V 3 V 4 3 V 4
The higher the v……... of the battery the more energy the electrons can t………... to the bulbs. voltage transfer filament light The bulb f………. heats up. Some of this heat energy is transformed to l…... energy.
Voltages in series circuits V V V 3 V 4 3 V 4
Voltages in series circuits V 3.0 V V V In a series circuit the voltage is shared across components 1.5 V 1.5 V
Voltages in series circuits 1.5 V 1.5 V V V V 3.0 V 0.2 A In a series circuit the voltage is shared across components
Voltages in series circuits A V V V 3.0 V 0.1 A In a series circuit the voltage is shared across components V V
Voltages in series circuits A 3 V 4 3 V 4 V V V 3.0 V 0.1 A In a series circuit the voltage is shared across components V V 3 V 4 3 V 4
Voltages in series circuits A 3 V 4 3 V 4 V V V 3.0 V 0.1 A Each bulb adds more resistance to the series circuit. The current flowing drops. The voltage across each bulb drops In a series circuit the voltage is shared across components V V 3 V 4 3 V 4
4.2 Potential difference ( pd ) and power Problem: If 30 J of work is done when 5C of charge passes through a component, calculate the potential difference across the component. V (Volt) = W (work done, J) Q (charge, C) V = 30 J = 6 V 5 C
4.2 Potential difference ( pd ) and power Problem: If 30 J of work is done when 5C of charge passes through a component, calculate the potential difference across the component. V (Volt) = W (work done, J) Q (charge, C) V = 30 J = 6 V 5 C
4.2 Potential difference ( pd ) and power EMF Electromotive force of a source of electricity: * is defined as the electrical energy produced per unit charge passing through the source W ( J) = (Volt) X Q ( C) Electrical energy produced when charge Q moves through the source