Magnetic Fields in Wires & Solenoids (OCR GCSE Physics A, Combined (Gateway Science Suite)): Revision Notes
📚 Revision Notes
7.2.1 Magnetic Fields in Wires & Solenoids
Current
- Current produces a magnetic field around the wire
- The direction is dictated by the "right hand grip rule"
- Plotting compasses on a piece of paper through which a wire is pierced shows this
Strength of Magnetic Field
- Greater current, stronger magnetic field
- Greater distance from the wire, weaker field
Solenoid
- Magnetic field shape is similar to a bar magnet
- It enhances the magnetic effect as coiling the wire causes the field to align and form a giant
single field, rather than lots of them all perpendicular to the direction of the current
infoNote
Having an iron core in the centre increases its strength as it is easier for magnetic field lines to pass through than air
- Factors that affect the strength
- Size of current
- Length
- Cross-sectional area
- Number of turns (coils)
- Using a soft iron core