Student Manual

This innovative experiment gives you an introduction of blackbody radiation and Planck's radiation law. The experimental objective involves the determination of the numerical value of Planck's constant using incandescent light bulb as a source of blackbody. Students will also practice error propagation and learn how to measure important parameters using weighted fit of a straight line.

Sample Results Logarithmic plot for finding the value of gamma
A graph of photo-intensity verus temperature to determine Planck's constant
Experiment Code 1.11
Version 5 January 2016, 2016-v1

Further Readings and References


Pictorial Procedure

1. Provided apparatus

1. Provided apparatus

2. This is how you'll measure the room temperature resistance of an incandescent light bulb

2. This is how you’ll measure the room temperature resistance of an incandescent light bulb

3. An assembly of optical components on the optical rail

3. An assembly of optical components on the optical rail

4. Place optical components inside the black box and insert cylindrical tube (having bulb fitted inside) into the black box

4. Place optical components inside the black box and insert cylindrical tube (having bulb fitted inside) into the black box

5. The incandescent light bulb is connected to the variac through an ammeter in series

5. The incandescent light bulb is connected to the variac through an ammeter in series

6. Circuitry of the setup. A voltmeter is connected in parallel configuration while an ammeter in series

6. Circuitry of the setup. A voltmeter is connected in parallel configuration while an ammeter in series

7. Rotate dial of the variac in clockwise direction to get variable voltages

7. Rotate dial of the variac in clockwise direction to get variable voltages

8. Connecting a photodetector to the digital oscilloscope

8. Connecting a photodetector to the digital oscilloscope

9. Adjusting voltage sensitivity range of a digital oscilloscope

9. Adjusting voltage sensitivity range of a digital oscilloscope