CourseGCSE Combined Science
GCSE Combined ScienceAQAGCSE PhysicsSoonGCSE ChemistrySoonGCSE BiologySoon

Potential difference and resistance: V = IR explained

Playing the video uses YouTube storage.Open on YouTube

Key ideas

  1. Potential difference (p.d.) is measured in volts (V) with a voltmeter placed in parallel.

  2. Resistance opposes the current. It is measured in ohms.

  3. p.d. = current × resistance, or V = I R.

  4. For a fixed p.d., a bigger resistance means a smaller current.