Determination of the Interference and Diffraction of Light (Edited)

Determination of Single-Slit Diffraction and Double-Slit Interference Using Laser Diode as the Source of Light Canopio, Marco 1, Marco, Ardin 2, Sirot, icardo !" 1

 Department of Geodetic Engineering, College of Engineering, Engineering, UP Diliman, Quezon City  Department of Mechanical Engineering, College of Engineering, Engineering, UP Diliman, Quezon City 3  Department of Mining, Metallurgical and Material Engineering, College of Engineering, UP Diliman, Quezon City !correponding author" ra#$1%%&'yahoo(com 2

Abstract The experiment aims to study the interference and diffraction of light  by investigating the patterns produced by single-slit and double-slit diffractio diffraction. n. The experiment experiment is divided divided into 3 parts- (1) investigati investigating ng the the patt patter ern n prod produc uced ed by diff diffra ract ctio ion n thro throug ugh h a sing single le slit slit and and determining its slit width, () investigating the pattern produced by diffraction through a double slit and calculating slit width, and (3) changing the slit width and slit separation of the diffraction produced from from a double double slit. The results results of the experime experiment nt contrib contribute uted d on understanding and studying the behavior of light.

I#

Introduction An RC circuit is a circuit composed of a power supply, a resistor and a capacitor. Capaci Capacito tors rs can store store electr electrica icall energy energy inside inside it when when charge charged, d, while while the resis resistor tor dissipates the energy to and from the resistor. In such circuits, it can be observed that the voltage, current and the power that ows through an RC circuit is not constant. The three quantities change with respect to time !". In the RC circuit, both the resistor and the capacitor are responsible for the time changing quantities. #hen connected to the power supply the capacitor will charge until it reaches its capacitance capacitance C. The charge in this capacitor will be equal equal to the product of  the capacitance and the voltage of the power supply $". %&ee, 'qn %!(( )* )

As the capacitor+s charge goes to qo, its voltage V  increases   increases to ) while its potential di-erence across the resistor decreases ". This relation results to 'quation %$(.

% (* (* )%!// 0  ( #hen discharging, however, at time t*), the charge q is equal to 1) or the ma2imum charge inside the capacitor. 3rom 1), the charge decreases until ir approaches 4ero at time t , and at the same time, the voltage V, from 5) also approaces 4ero, thus resulting to 'qn %(

% (* (* )%/ 0  (

t is the time constant given by t *RC from a circuit with resistance R and Capacitance C 6"

 The e2periment aims to quantify the rate of charging and discharging of a given capacitor that is in series with a resistor and power supply. 3rom it, e2perimental time constant could be measured and be compared with the theoretical time constant.

II# Methodolog$  The materials used in the e2periment were multimeter, !)))73 electrolytic capacitor, !)) 89 resistor, !) 89 resistor, connecting wires with clips, banana plug and stopwatch the e2periment was divided into  parts, %i( resistance and capacitance measurements, %ii( charging RC Circuit and %iii( discharging RC Circuit. 3or the :rst part, a single slit dis8 was used. #ith a slit width of ).)6mm, a laser beam was centered on the slit. Then, the hori4ontal distance from the slit dis8 to the screen was determined. The lights were turned o- so that mar8ing the boundaries of the dar8 fringes the beam made on the white sheet will be easier and more accurate. The distance between the side orders and from center to side was then measured. The :rst part was repeated for a slit width of ).)$mm and ).);. 3or the second part of the e2periment, the power supply was set between ne end of the resistor was connected to banana plug and the negative terminal of the capacitor was connected to blac8 banana plug. The capacitor was connected parallel to the voltmeter in ?C settings and with the 8nob set to $) 5. The power supply was turned on and the stopwatch was started as soon as the circuit was closed.  The third part of the e2periment, one lead of the resistor was connected to one lead of  the capacitor using alligator clips, li8ewise with the remaining free leads of both using another alligator clip. The terminals of the capacitor was connected to the corresponding terminal of the voltmeter in ?C settings and with the 8nob set at $) 5. The terminals of  the capacitor was connected to the corresponding terminals of the power supply. The power was set between %nterference and 6iffraction (*ab manual). 9rinted 11 &ugust $1/.