Unofre Pili, Renante Violanda
Presented in this article is an alternative and cost-effective method for measuring Planck's constant with light-emitting diodes (LEDs). Essential in the presentation is the apparent linear plot of the voltage against light intensity associated to each LED; such a plot reveals the threshold or minimum voltage that turns on the LED. Those threshold voltages associated to all LEDs used are theoretically related to the frequency of the emitted light and to the Planck's constant. Hence, in the experiment presented, the determination of the value of Planck's constant to be equal to 6.1(±1) × 10 -34 Js. This result is in error by 7.9% in comparison to the accepted value of 6.626 075 54 × 10 -34 Js but it appears to be good enough for educational use. © 2019 IOP Publishing Ltd.
Department of Physics, University of San Carlos, Cebu City, 6000, Philippines
