Hi, i have a graph with voltage (y axis) plotted against current (x axis) and I need to calculate the resistance of a resistor and a lamp from this.(adsbygoogle = window.adsbygoogle || []).push({});

My physics teacher has told me that by Ohm's law, R = V/I, and he has also told me that on the graph, the resistance is the gradient of the graph.

The graph for the resistor is linear, so V/I is the same as the gradient, I have no problem with this. However, the graph for the lamp is non linear, so V/I isn't the same as the gradient.

What's the correct answer here? Am I missing something blindingly obvious? Thanks for any help

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Calculating resistance from a graph

Loading...

Similar Threads - Calculating resistance graph | Date |
---|---|

Temperature rise calculation for electrical devices | Jan 30, 2018 |

How should I calculate conductivity | May 16, 2017 |

Limiting amps and volts from a battery | Mar 28, 2017 |

Thermistors calculation of base resistance | Nov 7, 2016 |

Positive Sequence Resistance and Reactance calculation | Aug 9, 2016 |

**Physics Forums - The Fusion of Science and Community**