Higher Physics Lab Atomic & Nuclear Physics

#### PLANCK'S CONSTANT BY LED SK014

Exp-1 Determination of material Constant h.
Exp-2 Determination of Temperature Coefficient of Current.
Exp-3 Determination of Planck's Constant by LED method.

• It is a self contained unit.
• Using LED method instead of photocell & monochromatic light source reduces cost.
• Built - in power supply for Oven (oven ambient to 60°C, resolution 0.1°C).
• Variable voltage source 0 - 2V DC, resolution 1mV.
• Current meter 0-20mA / 2000mA.
• In - built temperature sensor.
• Photoelectric effect.
• Photo cell.
• Work function.
• Planck's constant.
• Photoelectric voltage.
• Photon energy.

Principle and Working:
The photon energy by Einstein equation E=hv is equal to energy gap Eg between the valence and conduction bands. The energy Eg is equal to the energy barrier eV0, that electron have to overcome in going from n-doped side of diode junction to p-doped side when no external voltage V is applied to the diode.
In the p-doped side, electron recombine with holes releasing the energy Eg in the form of photon is given by equation

Eg = eV0

In the present setup ,the Planck Constant is given by

Contents:

 Cat. No. Item Name Qty. SEA95 Planck’s constant apparatus 1 SEB06 Oven 1 SEB09 LED red 1 SEB10 LED yellow 1
##### Planck’s Constant Apparatus SEA95
SPECIFICATIONS Selector Switch : V-I and T-I experiment
Selector Switch at V-I position :-
Voltmeter Display : 3½ digit, 7segment LED,auto polarity & decimal indication.
Voltage Range : 0.000-2.000V
Current Display : 3½ digit, 7segment LED
Current Range : 0-2000mA
Selector Switch at T-I position :-
Current Display : 3½ digit, 7segment LED
Current Range : 0-20mA
Temperature Display : 3½ digit, 7segment LED
Temperature Range : Room temperature to 60.0°C

Oven : Heater pin 4 & 5. Temperature pin 1 & 2
Oven Connector : 5 Pin, DIN type
LED Connector : 3 Pin, DIN type
Input Voltage : 220V, 50Hz AC
Fuse : 1A, 250 V
##### Oven With Temperature Sensor SEB06
SPECIFICATIONS Heating Element : 20 ohm
Oven Connector : 5 Pin, DIN type
Ambient Temperature : 60° C
Temperature Sensor : Pt100
Output Pin : Heater pin 4 & 5. Temperature pin 1 & 2