Phys 201 Lab
Name: Paul Dolphyne Ackah
Lab Partners: Keyra, Amos
Introduction
In this laboratory report, we explore the fascinating phenomenon of interference, which
occurs when two or more light waves of the same frequency overlap in space. This effect is
contingent on both the phases and amplitudes of the waves and cannot be comprehended
solely through ray optics or the particle-like nature of light. Instead, it necessitates the explicit
recognition of light's wave nature.
Two light sources are deemed coherent when they emit light waves of identical frequency
and maintain a constant phase relationship between them. The light emanating from such
sources is referred to as coherent light. Conversely, light from sources like lightbulbs,
candles, or stars is considered incoherent due to its lack of phase coherence.
It's worth noting that light waves are transverse waves. To observe interference using light
waves on a laboratory timescale, an additional condition must be met: the interfering waves
must share the same polarization. This can be achieved by using radiation from two different
parts of the same wavefront.
Procedure
In this experiment, we directed a laser beam, which emits coherent light, through a slit. The
slit's dimensions were controlled using an aperture bracket. The laser beam was focused on
the slit, positioned approximately 20 cm away, and then projected onto a viewing screen
situated 80 cm from the slit. This resulted in the formation of a horizontal interference
pattern.
We made adjustments to the slit sizes as necessary, using both 0.16 mm and 0.08 mm wide
slits.
We also conducted similar experiments with double slits. In these trials, we used a single slit
width of 0.04 mm, while the separation distance between the double slits, denoted as 'd,' was
set to either 0.25 mm or 0.50 mm.
To record and analyze our experimental data, we employed the PASCO Capstone application.
Data
Experiment 1: Single Slit a = 0.16mm
mL (cm) R (cm) (R-L) / 2 (cm) Theoretical (cm) % error
1 .0731 .0792 .00305 0.325 cm 6.15%
2 .0698 .0827 .00645 0.650 cm 0.77%
3 .0671 .0860 .00945 0.975 cm 3.08%
