SUMMARY
The electric field amplitude at a distance of 0.67 m from a 90 W lightbulb emitting light at a wavelength of 500 nm can be calculated using the relationship between intensity, power, and distance for spherical waves. The intensity (I) of the wave can be derived from the power (P) of the bulb and the distance (r) using the formula I = P / (4πr²). Subsequently, the electric field amplitude (E) can be determined from intensity using the equation I = (E²)/(2Z₀), where Z₀ is the impedance of free space (approximately 377 ohms).
PREREQUISITES
- Understanding of spherical wave propagation
- Knowledge of intensity and electric field relationships
- Familiarity with the concept of impedance in free space
- Basic proficiency in using formulas related to light and electromagnetic waves
NEXT STEPS
- Study the derivation of intensity formulas for spherical waves
- Learn about the relationship between intensity and electric field amplitude
- Explore the concept of impedance in electromagnetic theory
- Review the principles of light propagation and wavelength effects
USEFUL FOR
Students studying physics, particularly those focusing on electromagnetism and wave phenomena, as well as educators seeking to reinforce concepts related to electric fields and light intensity.