It appears the question asks to design an experiment to show the effect of a factor on the rate of photosynthesis, and then asks for the physical equation and procedure. The specific factor is not clearly visible in the image. I will assume the question is asking about the effect of light intensity on the rate of photosynthesis, as it is a common experiment. a. Physical equation for your experiment The overall chemical equation for photosynthesis is: $$6\text{CO}_2 + 6\text{H}_2\text{O} \xrightarrow{\text{light energy}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$$ This equation represents the conversion of carbon dioxide and water into glucose (a sugar) and oxygen, using light energy. b. Procedure Aim: To investigate the effect of light intensity on the rate of photosynthesis in an aquatic plant. Materials: Aquatic plant (e.g., Elodea or Cabomba*) Beaker or test tube Water (preferably distilled water with dissolved sodium hydrogen carbonate to provide CO$_2$) Light source (e.g., lamp) Ruler or meter stick Stopwatch Thermometer (optional, to monitor temperature) Method: 1. Preparation: Cut a fresh shoot of the aquatic plant about 5-10 cm long. Place the cut end of the plant shoot upwards in a beaker or test tube filled with water. Add a pinch of sodium hydrogen carbonate to the water to ensure a sufficient supply of carbon dioxide for photosynthesis. Ensure the cut end is clean and free of damage to allow for efficient oxygen bubble release. 2. Setup: Place the beaker/test tube containing the plant in a dark room or area to minimize external light interference. Position a light source (lamp) at a measured distance from the plant. This distance will determine the light intensity. 3. Experimentation (Varying Light Intensity): Step 1: Start with the light source at a specific distance (e.g., 10 cm) from the plant. Allow the plant to acclimatize for 5 minutes. Step 2: Start the stopwatch and count the number of oxygen bubbles released from the cut end of the plant in a fixed time period (e.g., 1 minute). Record this number. Step 3: Repeat the counting for at least two more 1-minute intervals at the same distance to ensure reliability and calculate an average. Step 4: Increase the distance between the light source and the plant (e.g., to 20 cm, 30 cm, 40 cm, etc.). This decreases the light intensity reaching the plant. Step 5: For each new distance (and thus new light intensity), repeat steps 2 and 3. Step 6: Ensure other factors like temperature (by using a heat shield or allowing cooling time) and CO$_2$ concentration remain constant throughout the experiment. 4. Data Collection: Record the distance of the light source from the plant and the corresponding average number of oxygen bubbles produced per minute in a table. 5. Analysis: Plot a graph with light intensity (which can be represented as $1/d^2$ where $d$ is the distance from the light source, or simply the distance itself) on the x-axis and the rate of oxygen bubble production (bubbles/minute) on the y-axis. Observe how the rate of photosynthesis changes with varying light intensity. Expected Results: As the light intensity increases (i.e., the lamp is moved closer to the plant), the rate of oxygen bubble production will generally increase up to a certain point, after which it may plateau due to other limiting factors (e.g., CO$_2$ concentration or temperature).