There are 10^10 photons per second incident on a photo-detector at wavelength 0.8 um. Compute the power incident on the detector. If this detector converts light to current at a rate of 0.65 mA/mW, what current is produced.
To compute the power incident on the photo-detector, we can use the formula:
Power = Number of photons per second * Energy per photon
Given that there are 10^10 photons per second and the wavelength is 0.8 um (or 0.8 * 10^-6 m), we can calculate the energy per photon using the equation:
Energy per photon = (Planck's constant * Speed of light) / Wavelength
Since Planck's constant (h) is approximately 6.626 x 10^-34 J·s and the speed of light (c) is around 3 x 10^8 m/s, we can substitute these values into the equation:
Energy per photon = (6.626 x 10^-34 J·s * 3 x 10^8 m/s) / 0.8 x 10^-6 m
Simplifying this equation will give us the energy per photon.
Once we have the power incident on the detector, we can calculate the current produced using the conversion rate of 0.65 mA/mW. We know that 0.65 mA is produced for every 1 mW of power.
Let's go through the calculations step by step:
1. Calculate the energy per photon:
Energy per photon = (6.626 x 10^-34 J·s * 3 x 10^8 m/s) / (0.8 x 10^-6 m).
2. Calculate the power incident on the detector:
Power = Number of photons per second * Energy per photon.
3. Convert the power to current:
Current = Power * Conversion rate.
By performing these calculations, we can determine the current produced by the photo-detector.