calculation or graphical methods. Analyse the results of the investigation to describe and explain how the resistance is affected. 4.2.1.4 Ohm’s law and the The current through an 1 Define what is meant by an Find the resistance of a conditions needed ohmic conductor (at a ohmic conductor. resistor by experiment. Plot for it to apply. constant temperature) is an I-V graph for the resistor, What components are ohmic directly proportional to the disconnecting the power Current-potential conductors? potential difference across supply unit between readings difference graphs the resistor. This means that Describe the conditions for which to let the resistor cool down. for electrical the resistance remains Calculate the resistance from Ohm’s law is valid. components. constant as the current the graph and compare with Explain why Ohm’s law is not changes. the known value from the when the temperature of the colour coding on the resistor. conductor increases in terms of collisions. Required practical *: Draw the I-V graph for an ohmic Use circuit diagrams to conductor. construct appropriate circuits to investigate the I–V Explain the shape of the I-V characteristics of a variety of graph of the ohmic conductor. circuit elements including a filament lamp, a diode and a resistor at constant temperature. (8.2.4)
calculation or graphical methods. Analyse the results of the investigation to describe and explain how the resistance is affected. 4.2.1.4 Ohm’s law and the conditions needed for it to apply. Current-potential difference graphs for electrical components. The current through an ohmic conductor (at a constant temperature) is directly proportional to the potential difference across the resistor. This means that the resistance remains constant as the current changes. 1 Define what is meant by an ohmic conductor. What components are ohmic conductors? Describe the conditions for which Ohm’s law is valid. Explain why Ohm’s law is not when the temperature of the conductor increases in terms of collisions. Draw the I-V graph for an ohmic conductor. Explain the shape of the I-V graph of the ohmic conductor. Find the resistance of a resistor by experiment. Plot an I-V graph for the resistor, disconnecting the power supply unit between readings to let the resistor cool down. Calculate the resistance from the graph and compare with the known value from the colour coding on the resistor. Required practical *: Use circuit diagrams to construct appropriate circuits to investigate the I–V characteristics of a variety of circuit elements including a filament lamp, a diode and a resistor at constant temperature. (8.2.4)
AQA-8463-SOW-ELEC.DOCX