To investigate how the vol flow rate depends upon the separation d of threads in the material
Diagram 1: Stretch out a piece of material using clips and retort stand. Using a container the top of the material allow a constant flow of water onto the material. Place a beaker at the bottom of the cloth to collect the water.
Diagram 2: Use a retort stand to hold the laser . Use a holder to stretch out the material in front of the laser. The light that passes through should fall on a screen a distance D away from the material.
Procedure:
1. Set up expt as in Diag 1. Start the stopwatch and replace a clean beaker to collect the water.
2. After a time t, stop the stopwatch and remove the beaker. Record the time interval as shown.
3. Measure the vol of water V collected using a measuring cylinder.
4. Calculate the flow rate by using the formula v = V/t.
5. Repeat steps 1 to 4 by varying the material of different d value.
6. The distance between the threads of the material used , d can be measure by using set up shown in diag. 2
7. Turn off the light and turn on the power of the laser.
8. Stretch the material vertically in front of the laser .
9. Using a ruler , measure the fringe spacing on the screen, keeping the distance D from the laser to the screen constant.The angle can be calc using tan angle formula.
The distance d can be measured using the formula dsin(angle) = n(wavelength) .
10. Repeat steps 7 to 9 by varing the material of different d . Matching the material and the flow rate it yields.
11. Plot a graph of lg v vs lg d . If the graph is linear , the equation v=kdn is valid ......
Control of variables:
1. The height from which the water was dropped should be kept constant .
2. The water falling onto material at a constant rate.
3. The tension on the material should be constant.
Reliability:
Repeat the measurement of fringe separation and averaging the value to calc angle .
Ensure the cloth is dry when used in diffraction expt
Wet the material before starting the volume rate measurement.
