A student investigated the effect of light intensity on the rate of photosynthesis in Elodea pondweed.
The table below shows the results of their investigation:
| Distance from the light source in cm | Volume of oxygen produced in 5 minutes in cm3\text{cm}^3cm3 | Light intensity in arbitrary units (a.u.) |
|---|---|---|
| 10 | 12.5 | 0.0100 |
| 20 | 10.2 | 0.0025 |
| 30 | 6.4 | 0.0011 |
| 50 | 1.8 | ? |
Calculate the light intensity at a distance of 50 cm from the light source.
State the inverse square law equation in your answer and show your working.
