3B Scientific Light Sensor User Manual

Page 4

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany •

www.3bscientific.com

Subject to technical amendments

6. Experimental applications

Investigation of the inverse square law for a point
light source

Properties of polarising filters

Demonstration of the flickering effect of alternat-
ing current for fluorescent lamps

Measurement of solar energy

Studies of reflection

Measurements of illuminance at work-stations and
personal areas

Relationship between light intensity and growth of
plants

7. Sample experiment

Investigation of the inverse square law for a
point light source

Apparatus needed:

1 3B NETlog

U11300

1 3B NETlab

U11310

1 Light sensor

U11364

1 Experimental lamp, halogen

U17140

1 Transformer 12 V, 60 VA

U13900-230

(alternative to the variable transformer shown in
Fig. 1)

1 Barrel foot

U8611200

1 Vertical ruler, 1 m

U8401560

2 Universal clamps

U13255

•

Set up the experiment as shown in Fig. 1.

•

On the 3B NETlab

, open the application pro-

gram (template) for the experiment with the
light sensor.

•

Lay the ruler horizontally, and fix the experi-
mental lamp at the 15 cm mark using one of
the universal clamps.

•

Define this point as distance zero, 0.

•

Mount the light sensor on the ruler using the
other universal clamp.

•

Connect the electric cables to the experimental
set-up and switch on.

•

Start the template program, select “manual
input”, and measure the light intensity at the
first point, a distance of 5 cm in front of the
experimental lamp.

•

Increase the distance in steps of 5 cm up to the
70 cm mark (a distance of 55 cm from the ex-
perimental lamp), and record the correspond-
ing light intensities in the 3B NETlab

(Fig. 2).

•

Generate the data curve using the “Fit” func-
tion.

Fig. 1 Investigation of the inverse square law for a point

light source

Fig. 2 Plot of the data points from the inverse square

law experiment on the monitor screen of the 3B
NETlab

(U11310)