Electromagnetic Radiation from Light Bulb
This interactive simulation calculates and visualizes the electric and magnetic fields produced by radiation from a light bulb at a specified distance. Adjust the parameters to see how they affect the field strengths.
Example 8.5: Electric and Magnetic Fields from a Bulb
Bulb Parameters
Measurement Parameters
Efficiency
Calculated Values
Intensity (I) = (Power × Efficiency) / (4πr²) = (100 × 2.5%) / (4 × π × 3.0²) = 0.022 W/m²
Erms = √(I/(ε₀c)) = √(0.022/((8.85×10⁻¹²)(3×10⁸))) = 2.9 V/m
E0 = √2 × Erms = 1.414 × 2.9 = 4.07 V/m
Brms = Erms/c = 2.9/(3×10⁸) = 9.6×10⁻⁹ T
B0 = √2 × Brms = 1.414 × 9.6×10⁻⁹ = 1.4×10⁻⁸ T
Comparison with Other EM Waves
- TV waves (~microvolts/m)
- FM radio waves (~millivolts/m)
- Earth's magnetic field (~50μT)
- Refrigerator magnet (~5mT)
