A student uses a magnetic field sensor to measure the strength of the magnetic field at different distances from a long straight wire.
The current in the wire is kept at 5.0 A.
The Table shows her results.
Table
| Distance from wire in cm\text{cm}cm | Strength of magnetic field in μT\mu\text{T}μT |
|---|---|
| 1.0 | 100 |
| 2.0 | 50 |
| 3.0 | 33 |
| 4.0 | 25 |
| 5.0 | 20 |
Describe the relationship between the distance from the wire and the strength of the magnetic field.
Use data from the Table in your answer.
Predict the strength of the magnetic field at a distance of 10.0 cm from the wire.
The student increases the current in the wire to 10.0 A.
State the effect this has on the strength of the magnetic field 2.0 cm from the wire.
Before she switches on the current, the student sets the reading on the sensor to zero.
Suggest why.
44 exam-style questions on OCR GCSE Physics 4.1 Magnets and magnetic fields, covering 4.1.1 Magnetic poles, attraction and repulsion, 4.1.2 Permanent and induced magnets, 4.1.3 The magnetic field of a magnet, 4.1.4 Compasses and the Earth's magnetic field, 4.1.5 The magnetic field around a current-carrying wire, 4.1.6 Field strength, current and distance, and 4.1.7 Solenoids and electromagnets. Each one has a worked solution and a mark scheme showing where the marks go.