10.3; 1. The figure shows that the top wave represents the current through the LED. The bottom wave shows the current going across the LED. The shape of the top wave works as a function of the current going through the LED. This means that each time the voltage surpasses the threshold (v turnon)the current passes through the LED and the light turns on. The figure shows how the current going across the LED is a function of the current going through the LED. 2. Wavelength (nm) 560 nm 585 nm 635 nm 660 nm 950 nm Frequency (10^14 Hz) 5.353 Hz 5.125 Hz 4.721 Hz 4.542 Hz 3.156 Hz Knee Voltage (V) 12.3 v 12.2 v 12.0 v 11.9 v 11.3 v 4. The accepted value for the slope of our Knee Voltage vs. Frequency graph (5 x 10-15 ) is h/e where h is planks constant and e is the elementary charge of an electron. 5. h/e = 5 x 10-15 e= 1.602 x 10-19 h/e x e = h m 5 x 10-15 x 1.602 x 10-19 = h m h m = 8 x 10-34 6. (│h m -h│/ h) h = 6.63 x 10-34 h m = 8 x 10-34 (│8 x 10-34 - 6.63 x 10-34 │/ 6.63 x 10
This is the end of the preview. Sign up
access the rest of the document.
This note was uploaded on 01/25/2011 for the course PHY 317k taught by Professor Kopp during the Spring '07 term at University of Texas at Austin.