Measuring Light Intensity

907 Words2 Pages

Abstract:

To investigate whether the relationship between light intensity varies inversely with the square of the distance holds truth in real-life situations and or under laboratory conditions. Furthermore, techniques utilised in the experiment included measuring the distance from the light source to the light sensor, recording the light intensity of a light source and recording observations with accuracy. The light from the light source that passes through the cardboard cylinder tube changes as the distance from the light sensor increases. The result shows that the relationship between light intensity varies inversely with the square of the distance holds truth in real-life situations and or under laboratory conditions.

Introduction:

The purpose of this experiment was to investigate whether the relationship between light intensity varies inversely with the square of the distance holds truth in real-life situations and or under laboratory conditions. Since, the light of a non-coherent light source will spread out uniformly in all directions. In other words, any point source which spreads its influence equally in all direction without limit to its range will obey the inverse square law. Luminous intensity is proportional to the inverse square of distance, I ∝1/r2. The light intensity is equal to the light reflux over watts. The light intensity is the power of the lighting energy and its unit is candle (cd). The unit for lighting reflux is lumen (lm).

It is hypothesised that if the distance increases the light intensity will decrease and therefore it will obey the inverse square law.

The graph above demonstrates that as the light sensor is further away from a light source, the less bright the source is. This mea...

... middle of paper ...

... tube.

5. The microscopic light was placed in the mouth of the cardboard cylinder tube, facing the light sensor.

6. The light sensor was connected to the lab quest.

7. The distance from the light sensor to the microscopic light was measured using the ruler. The distance was recorded into a data table.

8. The microscopic light was turned on by plugging into the wall socket.

9. The light sensor was turned on in order to measure the light intensity of the microscopic light. The data for the light intensity of the microscopic light was saved with an appropriate name into a USB flash drive. The data was recorded into a table at home.

10. Step 4, 5 and 6 was repeated three times but with different distances, different light sources such as LED light, and fluorescent light.

Under laboratory:

Repeat the procedure for the real-life situation but in a dark room.

Open Document