P2 Unit 5 lesson 1 Resistance & p.d/current graphs

Resistance & current/voltage graphsLesson P2 5.1/2/3

Aim: Calculate resistance (ohms) and draw current/p.d graphs for a wire, filament lamp and a diode.
Key words: Potential difference, resistance, voltage (p.d), current, filament lamp, diode.

Starter: Recap of circuits and introduction to Resistance equation...
Resistance (ohms) = Potential difference (Volts)/current (amperes).
R = V/I. Students try some examples to practice using the equation.

Main: Mr C will introduce current/p.d graphs and quickly demonstrate the circuit that you will need to set up. You will be changing the voltage in the circuit and measuring the effect this has on the current using an ammeter. You will then need to record your results in a table and plot them on a graph. The slope of the line represents the resistance in the circuit. Make sure you investigate the effect that wires, filament lamps and diodes have on resistance.
Write a short conclusion that summarises your observations. How do the various appliances effect resistance in electrical circuits (the slope of the graph).

Plenary: Mr C will go over what you should have observed during the experiment. Make sure you assess your own work so you know your understanding is correct.
To end the lesson Mr C will explain how thermistor’s and LDR’s (Light dependent resistors) affect resistance in a circuit. If there is time the summary questions on pg 239 of the textbook can be attempted.

Homework: from H/W book.

AQA Specification Link up
Physics 2.13.6