CD Diffraction

Objective:
Find the Diffraction of a CD.

  

 

 

 Data:

 

 

 

 

Conclusion:

We did really good, just 8.31%error.

The equation is really usuful.

just be carful. since the angle is really small and the distance is really small as well, sin is not equal to the angle. In this case, should using tan find the angle first. 

 



Lenses

 

Objective:

 The purpose of this lab is to analyze the characteristic of a biconvex lens and verify the relationship between the image distance, object distance, and focal length.

First find the force, by using the sun.



 

 

 

 Data：

 Graph:

 

One note not present in the data is that upon the reversal of our lens in the lens holder, the image underwent no change in height or orientation. As we extended the distance from the focal point, our  magnification grew less and less. We also were able to see that as we made the object distance within the focal length, the image was flipped. Using excel, I found, experimentally, that:

 

 

 

Error:

The error on this experiment can be mostly contributed to measurement error. We can contribute an error of about ±3cm on all measurement due to the increments of the ruler used, ruler that is not perfectly perpendicular with the paper and the light source, and the image that may not be completely focused on the screen.

 

     

Concave and Convex Mirrors

Objective:
The purpose of this experiment is to study the characteristics of the image created on a concave and convex mirror.
Convex mirror

  The image appears smaller than the object. The image is upright. When moved closer, image get lager, and as the object gets farther away from the mirror, the image size becomes a lot smaller.When the object moves further from the mirror, the image gets smaller, and it is still upright. Object distance becomes much larger than the image distance.

 

 

Concave mirror

 The image is smaller than the object, and it is inverted. The distance between object and the mirror is greater than the froce.The image becomes upright and the size is larger than the object. Image is closer to the mirror than the object.Image is still smaller than the object and inverted. The difference of distance become lager. The distance from mirro to object is less than the froce.

 

 

Conclusion

For the convex mirror,image is always upright and smaller than the object. For the convave mirror, when the object is close to the mirror, the image is upright and larger than the object, while the image is inverted and smaller than the object when the object is far from the mirror.

 

Introduction to Reflection and Refraction

Objective:
 The purpose of this experiment is to analyze the behavior of light as it travels from one medium to another, and to find the relationship between the index of refraction, the incident angle, and the refraction angle.

 Data:

graph:

The slope of this graph (1.5192) represents the ratio of index of refraction between the plastic and the air. Since the index of refraction of air is 1, we can conclude that the index of refraction of air is 1.5192

Part 2

Data can only be collected up to 40o because there is a critical angle at around 45o that would cause the ray to be totally internally reflected as shown.

 

    Data:

Grapg:



 

 

Conclusion: The ratio between the sine of the incident and the refracted angle is proportional to the ratio between the index of refraction of the two mediums at which light travels. This relationship is expressed in the Snell's Law:

n₁sinθ₁ = n₂sinθ₂

From the data gathered on part 1 and part, we can also conclude that the index of refraction of the plastic is around 1.5

 

 

 

Electromagnetic Radiation Lab

Purpose:

       The purpose of this experiment is to investigate the behavior of electromagnetic radiation due to a simple antenna.

 

 

DATA:

 

 

 

 

 

 

 

 

 

 
 

 
 





   
Data:

Grapg:

 

 

 

 

ANALYSIS:

The uncertainty values for the peak to peak voltage are as follows:

±12 for V= (50 mV, 90 mV)

±6 for V= (19 mV, 28 mV)

±3 for V= (7.5 mV, 15.5mV)

The quantization uncertainty in the measurements of the distance z was set to ±0.01 cm. However, this uncertainty distance that was measured may have been calculated to the base of the prong. Consequently , an additional uncertainty, ±.02cm, needs to be added making it a total ∆z uncertainty of ±0.03cm.

Z minimum	Z maximum	Vmax	Vmin	Vuncertainty
0.02	0.08	144.1614372	65.30877	39.42633133
0.07	0.13	71.97213324	44.16668	13.90272463
0.12	0.18	47.28534799	33.06248	7.111432949
0.17	0.23	34.83099292	26.31653	4.257233117
0.22	0.28	27.44228895	21.81686	2.812715339
0.27	0.33	22.59180341	18.61364	1.989079353
0.32	0.38	19.17788295	16.22204	1.477923748
0.37	0.43	16.65045626	14.37048	1.13998933
0.42	0.48	14.706491	12.8957	0.905395224
0.47	0.53	13.16610911	11.6939	0.736106122

 

 

 

 Conclusion:

We learned the behavior of electromagnetic radiation due to a simple antenna. The voltage and distance is the mots important two things. The range of error between the two could be explained by discussing the simplifications made in order to keep this experiment simple. Even though we assumed that the linear charge density was constant, there were also other outside interference that could have altered the effects of the radiation that would have given slightly inaccurate data from the oscillator. 

 

 

Introduction to Sound

ObjectiveUse sound sensor, logger pro, and tuning fork to study sound waves.

Procedure

Let first person say "AAAAAAA" into the microphone and collect the data

 

 Let another person do the same thing and record the data.

 

Strike the tuning fork and record the data

 



Data

 

First Person

 

 

Second Person

 

 



Stuck the tuning fork hardly

 

 

Struck the tuning fork softly

 Questions

1
a) Yes, it is repeating.
b) We observed 4 waves. We determined waves by group
c) Prob time is 0.03 seconds. It is about a blink of an eye.
d) The period of the waves is 0.0075 seconds
e) Frequency is 133Hz
f) Lambda =2.55m. It is about the height of the classroom
g) Amplitude is about 0.6115 (no unit)
h) There would be more waves, but the frequency, lambda, amplitude will stay the same
    test results: there are 38 waves, period become 0.00789, lambda becomes 2.68, Amplitude becomes 0.602

 

 

2
 18 waves, T=0.00167s, A=0.234, lambda=0.566m

3
8 waves, T=0.00375, A=0.0695, lambda=1.275

4
We expect to have the same frequency, wave length, sahpe, but different amplitudes.

    Struck softly


   Struck hardly

Standing wave

Objective

Determine the right relationship between spring length, velocity to create a standing wave with different frequency.

Data:

Data of Case 1 (collected from experiment)

1/ λ, 1/m	frequency, Hz
0.25	12.1
0.5	23.7
0.75	34.3
1	46.3
1.25	57.5
1.5	68.9
1.75	80.2
2	90.6
2.25	103.8
2.5	115.4

The Slope of the line (f vs.1/ λ) is 45.70m/s.

 

Data of Case 2 (collected from experiment)

1/ λ, 1/m	frequency, Hz
0.25	4.7
0.5	10.3
0.75	15.6
1	20.9
1.25	26.3
1.5	31.3
1.75	36.7
2	41.6
2.25	46.7
2.5	51.5

The Slope of the line (f vs.1/ λ) is 20.81m/s.

The ratio of the wave speeds for the two cases (from the graph) is r = 45.70/20.81 = 2.196

The ratio of the wave speeds (apply equation v=(T/u)^0.5) is r = (0.25/0.05)^0.5 = 2.236

There is a 1.8% difference between two ratios.

 

The ratios of frequencies for case 1 and case 2

1/ λ, 1/m	f1/f2
0.25	2.57
0.5	2.30
0.75	2.20
1	2.22
1.25	2.19
1.5	2.20
1.75	2.19
2	2.18
2.25	2.22
2.5	2.24

We can see that the ratios are close to the theoretical value 5^0.5=2.236 and have a difference lower than 10%.

 

 

 

When we measured the length and the weight in this lab, the uncertainties were lower than 1%. However, when we try to determine some high frequencies, we cannot determine the exact frequencies which generate the given wavelength (2L/n) because the standing wave becomes hazy as the frequency increases, and the uncertainty increases as the frequency gets higher. When the nodes created by the high frequencies are more than 8, the uncertainties of the frequencies are as high as 15%, which are significantly high. To reduce the uncertainty, we should make the length of the string that participate in oscillation longer and reduce the weight of the hanging mass.