Idiomas disponibles
Idiomas disponibles
3. Technical data
Operating voltage:
Maximum permissible
current:
Diodes:
Series resistor:
Connections:
Dimensions:
Weight:
4. Sample experiments
In order to conduct the experiments, the following
apparatus is additionally required:
1 DC power supply unit,
0-30 V, stabilised:
1 Multimeter, Escola 10
1 Stand base
Experiment leads
λ (nm)
Colour
465
Blue
560
Green
585
Yellow
635
Light red
660
Dark red
950
Infra-red
Elwe Didactic GmbH • Steinfelsstr. 6 • 08248 Klingenthal • Germany •
3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany •
6 V DC
20 mA, LED (infra-red)
100 mA
6 LEDs (blue, green, yellow,
and 3 different wavelengths
of red)
100 Ohm, 1 W
4-mm safety connectors
115 mm x 115 mm
120 g approx.
8521145
8531160
8611210
14
f in 10
Hz
f = c/ λ
6.45
5.36
5.12
4.72
4.54
3.15
Subject to technical amendments.
4.1 Determining Planck's constant (h)
•
Connect the diodes individually via the resistance
to the voltage source. Make sure they are forward
biased.
•
Switch on the power supply unit after setting it to
the minimum voltage.
•
Gradually increase the voltage.
The diodes light up when the bias voltage U
connections 1 and 4) has been reached.
For a wavelength of 950 nm, the light emission can be
observed through the viewfinder of a digital camera.
4.2 Evaluation
•
Calculate the frequency values from the wave-
lengths.
f = c/λ
•
Calculate the values for energy.
-19
E = e *10
·U
D ,
•
Based on the energy values in the E/f curve, calcu-
late the gradient of the curve.
•
Derive the constant (Planck's constant h) from
the gradient.
⋅
=
⋅
e
U
h
f
D
U
in V
D
Measurements
2.26
1.72
1.67
1.51
1.44
1.0
www.elwedidactic.com
www.3bscientific.com
(between
D
-19
E = e * U
in J*10
D
-19
(e = 1.602*10
As)
3.62
2.76
2.67
2.419
2.307
1.6
