Yes, it is possible to calculate the amplitude of a light wave when you know the intensity of the light. However, it is important to note that the relationship between amplitude and intensity is not a simple linear one.
In the context of light waves, the intensity represents the power per unit area carried by the wave. Mathematically, intensity (I) is defined as the average power (P) transmitted by the wave per unit area (A) perpendicular to the direction of propagation:
I = P / A
The amplitude of a light wave is related to its electric field strength. The relationship between amplitude (A) and intensity (I) can be described by the formula:
I = cε₀E₀²
Where:
- I is the intensity of the light wave,
- c is the speed of light in vacuum (approximately 3 x 10^8 meters per second),
- ε₀ is the electric constant (approximately 8.854 x 10^(-12) farads per meter),
- E₀ is the amplitude of the electric field.
From this equation, it is apparent that the intensity is proportional to the square of the amplitude of the electric field. Therefore, if you know the intensity of the light wave, you can calculate the amplitude of the electric field (and subsequently the amplitude of the light wave) by taking the square root of the intensity divided by the product of c and ε₀.
A = √(I / (cε₀))
Keep in mind that this formula assumes the light wave is a simple monochromatic wave with a single frequency. For more complex waveforms or situations, the relationship between intensity and amplitude may be more involved.