SUMMARY
The discussion centers on calculating the maximum possible magnetic flux density near a child sleeping 30 cm from household wiring carrying 3.6 kW of power at 240V r.m.s. The correct approach involves using the formula B = (μ0 * I) / (2π * r) to determine the magnetic field strength, where I is the current calculated from the power and voltage. The participants clarify that the r.m.s. voltage is an average value, and the peak voltage is approximately 1.414 times the r.m.s. value. The confusion arises from discrepancies in the current values used, with one participant concluding that the mark scheme's use of 21.2 A is incorrect.
PREREQUISITES
- Understanding of AC voltage and current, specifically r.m.s. and peak values.
- Familiarity with magnetic flux density calculations.
- Knowledge of Ohm's Law and power equations in electrical circuits.
- Basic grasp of electromagnetism principles, particularly the relationship between current and magnetic fields.
NEXT STEPS
- Study the relationship between r.m.s. and peak values in AC circuits.
- Learn how to calculate magnetic flux density using different current values.
- Investigate the effects of voltage variations on current in AC systems.
- Explore common mistakes in electrical calculations and how to avoid them.
USEFUL FOR
Students studying physics, electrical engineers, and anyone involved in electrical safety and design, particularly those interested in the effects of electromagnetic fields on human health.
