Type of bulb Energy (J) Stated power (w)

Time (s) Actual Power (w) (2dp)

Florescent 1 1000 9 49.26 20.30

Florescent 2 1000 11 16.11 62.07

Filament 1 1000 25 38.15 26.21

Filament 2 1000 150 7.30 136.99

Filament 3 1000 40 24.41 40.97

Filament 4 1000 10 89.88 11.12

Filament 5 1000 100 10.46 95.60

Filament 6 1000 40 23.94 41.77

Filament 7 1000 60 16.11 62.07

Actual power calculated using the formula :

Power = energy (j) / time (s)

PART A

Type of bulb

Stated power

Actual power

Tolerance (%)

Filament 10 11.12 +1.12

Filament 25 26.21 +4.84

Filament 40 40.97 +2.425

Filament 40 41.77 +4.425

Filament 60 62.07 +3.45

Filament 100 95.60 -4.40

Filament 150 136.99 -8.67

Fluorescent 9 16.11 +79.00

Fluorescent 11 49.26 +347.82Tolerance calculated by: [actual power (w) / stated power (w)] X 100

Type of bulb Stated power (w)

Light Intensity

Florescent 1 9 36.13Florescent 2 11 144.20Filament 1 25 2973.63Filament 2 150 15698.09Filament 3 40 4982.76Filament 4 10 1778.41Filament 5 100 14550.93Filament 6 40 3720.25Filament 7 60 9821.32

PART B

Florescent bulbs

Highest value = 15698.09

(i) The independent variable in our experiment was the light bulbs.

(ii) The sensitivity of the GLX was 0.01

(iii) ??????

(iv) Using the graph we can see that light intensity depends on power. The more power you have the higher the light intensity. ????? What else can we put :S

PART B

What can we do in future?

• Plan the experiment first! Timing is essential.

• Definitely read up on your experiment before hand

• If you can, try and get more results so you can have a more accurate set of results

• Draw tables before hand – saves time!

*Notes

* One of our florescent bulbs was broken

* Had to put our GLX on top of our books to try and keep it in the same position for each bulb – moving it could greatly affect results

* Reaction times in terms of stopping the stop watch will have affected our results. (human error)