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# GCSE: Waves

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1.  ## Investigate how the angle of refraction is affected by different inputs of the angle of incidence through a glass block.

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In other words the angle of refraction is less than the angle of incidence. When light leaves a transparent material, it bends away from the normal. Snell's law The law of refraction relates the angle of incidence (angle between the incident ray and the normal) to the angle of refraction (angle between the refracted ray and the normal). This law, credited to Willebrord Snell, states that the ratio of the sine of the angle of incidence, i, to the sine of the angle of refraction, r, is equal to the ratio of the speed of light in the original medium, vi , to the speed of light in the refracting medium, vr , or sin i /sin r = vi / vr .

• Word count: 891
2.  ## Experiment to Investigate which Factors Affect the Strength of an Electromagnet

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Variables The variables are the number of coils and the strength of the magnet. The number of coils I will change is in the independent variable and the strength of the magnet is the dependent variable. What I Intend to do I intend to investigate which factors affect the strength of an electromagnet. I intend to keep the voltage the same throughout the experiment I'm going to keep adding coils to the solanoid and find out how many paper clips it attracts. Apparatus Power Supply DC 0 - 13v demagnetising solanoid Connecting wires with plugs Crocodile clips Insulating wire (approximately 1m)

• Word count: 560
3.  ## Optics - the human eye and coomon defects

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The amount of light entering the eye is controlled by the Iris. Sharp focusing is achieved by altering the shape of the lens. The shape of the lens is controlled by the ring of ciliary muscle which runs round the outside of the lens. (http://www.riverdeep.net/current/2002/01/012002_images/eye.jpg) Defects in the eye:- 1. Long Sight (Hypermetropia) In this condition we can see distant objects more clearly that ones that are nearby. This is usually because the cornea is not curved enough, which reduces the angle of refraction, and the lens cannot accommodate sufficiently to bring the diverging rays from near objects into sharp focus on the retina.

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4.  ## Physics of water waves.

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After reflection the wave has the same speed, frequency and wavelength as it did prior to the collision. This is similar to the reflection of circular waves off a straight barrier. The reflected waves are also circular, however they have a centre point that is position behind the barrier. This point is known as the "image" of the source. Reflection of a parabolic or concave barrier can be closely compared to that of light waves off a concave mirror. If the incident wave was straight, the reflected waves are curved, and they converge at a fixed focal point.

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5.  ## The Electromagnetic Spectrum.

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Microwaves Microwaves have frequencies between 1010 and 1011 Hz, and have a wavelength of 10-2 to 10-3 , they are produced by microwaves, ovens and microwave transmitters and are detected by microwave receivers. We use them in cooking foods, communication and radar so when you use a microwave you're using microwaves or when you're using a mobile phone you're using microwaves. Infrared Infrared covers waves with wavelengths between 1mm to 50 nm and frequencies from 300GHz to 400 THz; however it can be split into three different parts: * Far - Infrared Wavelength: 1 mm -10 �m Frequencies: 300 GHz

• Word count: 730
6.  ## What causes feedback in a guitar or microphone?

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Let's deal first with the simple case of a microphone and an amplified speaker. (See the figure, but ignore the guitar for now.) Feedback occurs when a "loop" between an input and output is closed. In this scenario, the microphone serves as the input and the amplified speaker provides the output. In our example, the loop between the input and output closes when the sound radiated from the amplified speaker reaches the microphone and is subsequently amplified again. In effect, the cat is chasing its tail. (See the dashed red line connecting the loudspeaker to the microphone through acoustic feedback in the figure.)

• Word count: 586
7.  ## The Fundamentals of Radio Wave Propagation

The answer, in three words, is radio wave propagation. Radio wave propagation theory is of particular importance to wireless communications, for, without a preliminary understanding of the physical nature of wave propagation it is impossible to ensure that communications can be established at all. * Transmission and Reception In a wireless environment radio frequencies are transmitted outward from a source, which is usually an antenna.

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8.  ## Electromagnetic Wave

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9. ## Insulation Materials Experiment Method We put 100ml of water at 80C into each of 6 beakers. Each beaker had a different material wrapped around it, and we measured the amount of time taken for the temperature of the water to decrease by 10C to 70C

Results Time taken for each attempt (seconds) Material 1 2 3 Average time (seconds) Polystyrene 179 192 201 190.67 Carpet 201 190 191 194 Bubblewrap 190 225 194 203 Fibreglass 213 178 198 196.33 Tissue paper 172 169 225 188.67 Cotton 162 176 - 169 Conclusion From our results wee can conclude that bubblewrap is the best insulator tested. It took an average of 203 seconds to lose enough heat energy to the atmosphere to reduce the temperature of the water to 70�C.

• Word count: 393
10. ## Focal length of Concave and Convex lens

With mathematical simplification, the Lensmaker's equation can be applied as follow . Procedure Type A is a convex lens with shorter diameter B is a convex lens with longer diameter METHOD I, We put the lens in front of the window and then try to obtain a sharp image on the screen. When we get a sharp image, then measure the distance between the screen and the lens and name it as F. The distance, F, is the focal length of the lens. Method II First, put a light source with a transparent object F in front of a convex lens.

• Word count: 786
11. ## refractive index prac report

Materials: Geoliner or Protractor, Power Pack Light Kit & accessories, White paper Method: Analysis Angle of Incidence Refracted Angle 5 4 10 6 15 8.5 20 10 25 13 30 16 35 19 40 22 45 26 50 27.5 55 29.5 60 33.5 65 35.5 70 36.5 75 37 80 37.5 85 38 It can be seen that from the table, the light ray is bent towards the normal because the angle of incidence is greater than the refracted angle thus stating that the Perspex block is of a greater density than air.

• Word count: 699
12. ## Measuring the speed of light

This was because of the extra time it took for the light to cross the extra distance. He calculated that it would take about 22 minutes to cross the diameter of Earths orbit. Using these calculations R�mer found the speed of light. He measured the distance between the sun and Earth and found out that the speed of light was 125,000 miles per second. James Bradley (1728) was not satisfied, he said that starlight could cause an "aberration of light" and could cause speed of light measurements go wrong. R�mer used an Astronomical method. Hippolyte Fizeau in 1849 used an earthbound method to measure the speed of light.

• Word count: 678
13. ## Convection - What it is and how it works

Heated air rising is an example of natural convection. Forced convection is when a pump or a mechanism moves the heated fluid. Some examples of forced convection are some types of ovens, refrigerators and air conditioners. Lava Lamp A lava lamp is an example of convection the heater in the base of the lamp heat up the fake lava. Due to the rapidly increased temp the lava expands making it less dense than the surrounding liquid. The less dense lava then floats to the top.

• Word count: 502
14. ## Find the refractive index of a plastic block.

Once the refracted ray disappears, the angle of incidence is the critical angle. You should start seeing a reflected ray coming out of the plastic block as shown above. 4. Plot points on the paper to show the light rays. Connect the points to form lines. 5. Draw normal on the paper between the incident ray and reflected ray as shown. Measure angle i (angle of incidence, critical angle) 6. Repeat step 3 to 5 at least 3 times to get sufficient results. Snell's Law method: 1. Set up the apparatus as shown.

• Word count: 614
15. ## Measure how the number of coils of insulated wire around the iron nail effects the amount of paper clips attracted to the electromagnet.

I believe that when more coils are added, the strength of the magnet will increase therefore it will be able to attract more paper clips. I believe this will happen because as more coils are wrapped around the core, the magnetic field gets stronger and stronger. For this investigation I will be changing the amount of coils to increase the magnetic fields strength. I will increase the amount of coils by 5 for every experiment. I will start with 5 coils of wire, then move onto 10, 15 etc up to 45.

• Word count: 829
16. ## The purpose of this experiment is to understand the law of reflection using the simplest way to see the phenomenon.

(see figure 1) When light is reflected on a polished and smooth surface such as a mirror, an image is produced, which appears to be at the same distance as the source of light. (see figure 2) My hypothesis for this experiment is that we will be able to see the basic laws of reflections being applied when shooting the light to a plane surface mirror and that the angle of incidence will equal the reflected ray. Experimental Method: The way that this experiment will serve its purpose is by using a mirror and the appropriate equipment to observe the law of reflection of light being applied.

• Word count: 875
17. ## Find out which supermarket the public prefers.

�0 - �40 �40.01 - �80 �80.01 - �120 �120.01 - �160 �160.01 - �200 �200 > 5) How long does your journey take? 0 - 20 minutes 21 - 40 minutes 41 - 60 minutes 60 minutes > Group Tally Frequency Mid point Frequency x Mid point �0 - �40 0 20 20 �40.01 - 80 l l 2 60 120 �80.01 - �120 l l l 3 100 300 �120.01 - �160 l l l l l l l l l l l l 15 140 2100 �160.01 - �200 l l l l l l l l l l l l l l l l 20 180 360 �200 > 0 220 220 40 3120 Mean = Total (Mid Point x Frequency)

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18. ## To Investigate what Factors Affect Reflection.

If I double the angle of incidence the angle of refraction will also be doubled- Angle I=20 Angle r=14 When doubled Angle I=40 Angle r=28 This does not happen on my averaged results, which means that my graph is not accurate. This means that my Graph does not support my prediction. A better way of getting results that are more proportional would be to use 'Snell's Law'. This means that you multiply the angle of incidence by sin and the angle of refraction also by sin; separately.

• Word count: 892
19. ## Making Sense of Data.

The amplitudes of both waves are added together, thus making the overall amplitude bigger. Therefore, we hear an increase in volume when the waves are superposed. These vibrations extend a little out of the edge of the tube. The distance extended, or end correction (c), is directly proportional to the radius of the pipe: c = 0.58 � radius You can also find the end correction by constructing the graph with the reciprocal of the frequency against the length of the pipe. The difference between zero and the point at which the trend line crosses the x-axis will give you the end correction of the pipe. This is the equation of the trend line.

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20. ## To Plan and perform an investigation to show how the strength of magnetism in an electromagnet is affected by the number of coils.

If there is one coil, and another is added, then the two coils have twice the strength of one. This is because the current going through the wire makes the iron nail an electromagnet, with more wire the nail will become more magnetised. The strength of the electromagnet can also increase if the current in the wire is increased. Diagram and apparatus nail wire Ammeter Power pack Top pan balance Iron fillings Method 1. Wrap the wire around the nail 20 times 2. Then connect the wire to the ammeter 3. Then connect the wire to the Power pack 4. Mark a height on the nail where u are going to dip the nail into the iron filings 5.

• Word count: 742
21. ## Forced vibrations, resonance and damping.

This resistance box varies the amount of electromagnetic damping to the set figure. Once we have done this we will then record the time it takes for 20 oscillations to occur and then calculate the time for one oscillation. Then using this we cam calculated the natural frequency of oscillation of the coil. For each setting, we will then recorded the amplitude of the oscillations shown on the galvanometer. Once this was all done we began our experiment and we can change the frequency on the signal generator and recorded the amplitude. Below are the results from the experiment.

• Word count: 833
22. ## Investigating the factors that affect the strength of an electromagnet.

> Which measurements have the largest errors? > Any improvements that I would make to my investigation. Planning What I am trying to find out? My aim is to find out the factors that affect the strength of an electromagnet. What I am going to do? Equipment list * Power pack * (Soft) Iron core * Wire * Paper clips Method In my investigation I am going to see how many paper clips an electromagnet can pick up, varying how many times a wire is wrapped around an iron core. 1. I will connect the wire to the power pack and set the voltage to 8.

• Word count: 770
23. ## Our aim is to find the factors, which make the strongest electromagnets.

My partner and I chose to change the amount of coils around the nail, for our experiment. PREDICTION I predict that the more coils we add to the electromagnet, the stronger the magnetism will be and therefore the larger amount of paperclips the magnet will be able to suspend. So if you double the amount of coils, than the magnet will pick up double the amount of paperclips.

• Word count: 387
24. ## Physics Essay: Making Music

In the case of producing sounds the waves usually travel through the air, as a longitudinal wave. This longitudinal wave is caused by vibrations, which alternately compress, then decompress the particles in the medium (e.g. air or water) through which the wave is travelling. These vibrating particles transfer energy. This diagram shows how the sound waves travel through its medium. (Sound always requires this medium so that the particles can vibrate, and carry the wave. Therefore sound cannot travel through a vacuum.) As sound is a wave it follows the many rules of waves, these include the importance of frequency and wavelength.

• Word count: 742
25. ## Investigation between the angle of Incidence and detraction

To help to complete this I shall draw up an equipment list before hand to help to make my investigation run smoothly the list is as follows: 1.

• Word count: 357