To stop the surrounding of the light bulb to rise in temperature, the halogen light bulb is contained in a stronger glass like quartz. This is because it is harder to heat up stronger glass and also it doesn’t brake easily.
Advantages and disadvantages of using a tungsten light bulb
Outdoor
Solar yard light are used in the outdoors. This is because the energy is made and stored from then sun and then it is used when it is dark.
Below is a diagram of a solar yard light.
The solar yard lamp consists of the following things:-
- A case made from plastic
- Solar panel on top made from solar cells
- A single AA NiCad battery
- A controller board
- An LED light source
- A normal tungsten light bulb
The solar panel is formed from many different solar cell. Each cell produce 0.45 Volts of energy when the light hits it. The amount of current in the solar cell depends on the size of the cell and the amount of light that hits the cell. If lots of cells are put together, then this produces a bigger amount of energy. This is why the solar panel has cell in series to each other.
The solar panels are connected to the battery. This battery is charged by the solar panels at daytime. The battery can reach a maximum charge of about 700 milliamp hours and produces 1.2 volts of power.
The LED turns the light on and off depending on the brightness of the day. If it becomes dark (night), then the LED turns the light on by allowing the stored power from the battery to be used for the light. And when it become bright (daytime) the led turns the light off day stopping the power supply from the battery to the light bulb.
This way that the bulb produces the light is the same to the way a normal tungsten light bulb works. The only difference is that this time the power supply is coming form the sun (solar power)
The reason why this lamp is best for outdoor use is because most of the sun light will hit the solar panel out side the house. This means that this light cannot be used indoors.
Advantages and disadvantages of using a tungsten light bulb
Task 2
As apart of this task, I will be seeing the different colours of the electromagnetic spectrum that is produced from the following domestic light sources:-
- Hot filament bulb
- Fluorescent tubes
- Energy saving filament (ESF) bulb
I will compare these light sources with the natural light spectrum.
When doing this experiment, I used a hand held spectroscope and tested different sources of light. The table below shows the different colours that where visible in the spectrum with the different light source.
Results
Fluorescent compared with natural light
When looking at the colours of the spectrum of fluorescent light, I can see that the colours are very similar apart from the colour indigo and yellow which was missing in the fluorescent light. This must mast mean that the colours was absorbed by the fluorescent atoms.
Energy saving filament (ESF) bulb compared with natural light
This was the same as the fluorescent light source. This is because the colour indigo could not be seen but, this light also had the colour yellow, which the fluorescent light didn’t have.
Hot filament compared with natural light
This spectrum had the colours red, and indigo missing when compared with the natural light.
TASK 3
As a part of this task, I will be using a spectrometer and a diffraction grating to work out the wavelength of a sodium lamp light. Below is a diagram of a spectrometer.
The diffraction grating has many slits in it. this could be as many as 10,000 per cm. when a light source is passed through the diffraction grating, a pattern of interference fringes is seen on the other side of the grating. When a monochromatic light (single wavelength) light is passed through the grating at 90o form the grating, on the other side of the grating, a interference fringes are formed. This has been shown in the diagram below.
Measurements that need to be taken to work out the wavelength of the wave
The formula below is the general formula that can be rearranged to work out the wavelength of the light.
Order of angular separation x wavelength (γ) = distance between slits (d) x angle(sin θ)
The formula can be rearranged to work out the wavelength of the light that passes through the diffraction grating. This has been shown below.
Wavelength(γ) =distance between slits (d) x angle(sin θ)
Order of angular separation (n)
γ = d sin θ
n
from looking at this formula, I can see that I would need to take the following readings to be able to work out the wavelength of the sodium light.
- Distance between the slits on the diffraction grating. This depends on the grating that is used.
- The angle at which the telescope is placed for the grating. This is found by looking a the venire scale.
- Order of the angular separation of the interference fringes. This is found by observation.
Working out the wavelength of a sodium light source.
For this experiment, I used a diffraction grating which had 1092 slits per centimetre. To work out the distance between each slot, I must divide 0.01m by 1092 as the value for d must be in metres . this Has been done below.
Value for d (distance between slits)
0.01 .
1092
Order of the angular separation (n) and angle (sin θ)
Is was worked out by moving the telescope to the first of the interference fringes for zero angle. This meant that the order I used was 1 which was the value for n. and then to work out the angle of 1 order, I looked at the venire scale, which read 28o. this means that the value For sin θ which is sin 28o.
Using all three of these values, I can work out the wavelength for a sodium light. This has been worked out below.
Wavelength (γ) = 9.16 x 10-6m x sin 28o
1
wavelength of a sodium light = 4.3 x 10-6 m = 430 nm.
Task 4 – planning
as a part of the plan, I will be planning a series of experiment to measure the light out put of different powered lights using a Lux meter and a LDR. A the end of the plan, I will decide the best method to use for this experiment and make any modifactions if needed.
Below I have listed the equipment I will be using.
- 5 different light bulbs with different voltages
- A power pack and some leads
- Small table lamp
- A black tube with two wires coming out of it (at the back)
- A bulb holder
- 2 x Clamp and stand
- 2 one metre rulers
- Lux meter
- LDR
Below, I have listed the different powered lights I will be using
with the five different bulbs, I will be comparing the different light intensity from different distance. I have chosen these five bulbs as they all have more of a different power out put. This will make it easier for me to plot a graph.
Below is a table to show the different kind of reading I will be taking using both the LDR and the Lux meter and the different distance I will be taking it from.
The diagram and the description below shows the two different methods I used for the trailing experiment.
LDR experiment
In this method, I had a LDR which was in a black tube to stop all other light apart from the bulb. The light bulb was placed on a ruler at the point of 0 cm. then the tube holding the LDR was brought to the different distances from the light. And the reading of the resistant was taken down.
Lux meter experiment
For this method, I used a Lux meter and held if from different lengths from the light bulb. This didn’t have any tube blocking unwanted light from getting to it.
Chosen method
I have decide that the both the methods above are the best methods to use. This is because they would give the best accurate results. I have made a modification to asks the teacher to close the blinds to stops any other light from interfiling with the accuracy of the results.
Time scale
Below I have planned a 8 week time scale.
Prediction
I am expecting the results to be something like the graph I have shown below for all the results.
Task 4 – write up
Below I have shown the result for the experiment. I have presented the tables for each bulbs separately.
Results : Royal blue 0.5 watts power
Graph: for 0.5 watts bulb (Lux against ohms)
Results : Royal blue 10.5 watts power
Graph: for 10.5 watts bulb (Lux against ohms)
Results : Orange 6 watts
Graph: for orange 6 watts
Results for white 6.5 watts
Graph for white 6.5 watts
Results for green 12 watts
Graph for green 12 watts
Task 5
as a part of this task, I have decided to discuss the uses of a fluorescent light tube. The diagram below shows how it looks.
The way that this light tube works has been explained below.
Electrons from the cathode are transmitted into the tube. In side the tube is mercury vapour and argon gas. When the electrons hit the mercury vapour, the vapour turns into gas. This happens because the electron from the cathode hits the electrons in the mercury vapour bond and which brakes the bond and in doing so, it releases a photon of energy. This photon is the visible light that is produced when a light bulb is turned on.
A fluorescent light tube is used in many stores. The reason it is used is mainly because it has a higher range of different coloured wave lengths in the spectrum that is produces. This has been shown in task 2. in task 2, I can see that a fluorescent light tube produces the following colours in the spectrum:-
- Red
- Orange
- Green
- Blue
- Violet
When this is compared with a tungsten light bulb, which produces:-
- Orange
- Yellow
- Green
- Blue
- Violet
We can see that fluorescent light tube produces more colours.
This is very important in stores. For example, if a fluorescent light tube was not used in a clothes shop, then the colour of all the clothes would not be able to be seen properly. This would have meant that customers would think that the colour of the clothes is different to what it really is.
by using a fluorescent light tube in stores, it has made the customers see the true colours of the produces they are about to buy. This make the fluorescent light tube good for its purpose.
The fluorescent light tube is shaped in a long tube (shown in the last page) and when it is placed in a sop floor, it is in parallel with other fluorescent light tubes. This has been shown in the diagram below. .
In task 4, I have seen that the light intensity decreases with the distances. Because the tube is long, this increases the surface area of the light out put. this means that the light covers a bigger are. This means that there is a less of a chance of light intensity dropping in some parts of the area that the light covers because the light covers a bigger area.
Fluorescent lights
Electrons from the cathode are transmitted into the tube. In side the tube is mercury vapour and argon gas. When the electrons hit the mercury vapour, the vapour turns into gas. This happens because the electron from the cathode hits the electrons in the mercury vapour bond and which brakes the bond and in doing so, it releases a photon of energy. This photon is the visible light that is produced when a light bulb is turned on.
Advantages:
They give out 99% of their light to their surroundings and they lose the other 1% as heat.
The cost of running this light bulb is a lot less then any other light bulb.
They are long so it provides more light. This is because it has a more mercury in the bulb, which means more light.
It has a bigger range of colours in the spectrum it produces. This allows different colours to be seen.
It has a very long life time of 10,000 hours.
Disadvantage:
When you switch on the lights, they take couple of seconds before they actually become fully bright
The glass tube that the light is produced from is very fragile. This means that it can brake easily.
As you get more far from the light source, the light intensity drops. This means it is header to see.
It can be blinding at high powers.
Street lights
Street lights work in the same way as a fluorescent light but the only difference is that streetlights contain a sodium spectrum instead of mercury. This reduces light pollution. They also use reflectors to shine light in the same direction.
Advantages:
Helps brighten up the street at night so cars and people can go out and about.
Disadvantage:
Everything is more yellow and dim. Not like sun light.
Filament light bulb
There are many different shapes and sizes of Incandescent lamps. They also have a number of different fittings. The colour of the glass can be changed to produce a different coloured light.
The light bulb has a tungsten filament inside it with an argon gas. The movement of the electrons in the atom of the tungsten produced the light that is visible. The argon all gas stops the tungsten from reacting with the tungsten.
The are many different uses for this light bulb. The mean one being the fact that it can be used to see in the dark.
Advantages :-
The tungsten light does not cost a lot to make and it has a very simple structure.
The tungsten metal wire that is used is a good conductor, which allow is to get very bright with a small piece of wire
The glass that is used to cover the tungsten precedes protection for the heating of the tungsten with gets hotter then 2400oC.
The light that is produced form the light bulb allows as to see when it is dark.
The light bulb is easy to fit onto the socket. So this means that it can be change by an untrained person.
They can be used to produce all different coloured light by placing different filters.
Disadvantage:-
The glass that is used to cover the bulb can easily break and cause harm to people.
The tungsten can get used up as all the electrons start to run out of the atoms. This means that the bulbs stops working.
The light can take some time to brighten up as the tungsten takes a bit of time to warm up.
The tungsten wire is very sensitive and if the bulb is drop or shaken, the tungsten wire can brake of ripe which stop the bulb from working
The tungsten wire is very sensitive and if the bulb is drop or shaken, the tungsten wire can brake of ripe which stop the bulb from working.
The light bulb gets very hot after it has been used. If a person touches it, then it will burn them.
The life time of the bulb is reduced by constant use of the bulb
halogen light bulbs
With halogen light bulbs, the gas that is in the bulb is different from the normal light bulbs. Mostly halogen light bulbs contain iodine of bromine. When the tungsten evaporates from the surface at high temperatures, it combines with the halogen gases. For the tungsten to stay combined with the halogen gases, the temperature of the surrounding must be 200OC. this stops the tungsten partials from condensing on the glass in with the tungsten is contained, which stops it from the glass getting cloudier. This means that the light intensity always stays the same in a halogen light unlike a normal light bulb.
Halogen light bulbs also have a wider rage of colours in the spectrum.
Advantages:-
They have 5 times longer lifetime then normal light bulbs. This means that they need to be changed less often and money is saved.
The light intensity is always kept constant, as the glass does not get cloudier.
A halogen light is brighter then normal light bulbs.
Gives very good colour rendering as it produces a whit light.
Halogen light bulbs provide full light intensity when it is turned on. It does not need time to warm up.
Disadvantages :-
Halogen light bulbs operate at higher temperatures then normal light bulbs. This means that there is a bigger risk of getting burns from the bulb
Halogen light bulbs can brake or even explode as they are made from glass. If the glass is hot, it can start a fire.
If shielding brakes, then it exposes ultraviolet light to surrounding.
They cost more then normal light bulbs
Halogen light bulbs above the power of 300 Watts have a higher risk of starting a fire. For this reason, they are not allowed for dormitory uses
solar yard lamp
A solar yard lamp uses a solar panel to charge the battery at day time and then at night time, the charged battery is used to power a tungsten light bulb.
Advantage
The good thing about a solar powered produced is that there is no electric used as the power is supplied by the sun. This means that there is no bill.
There is no wires that are needed for the light. This makes it less fiddly.
The light atomically turns off and on. This means that when the light is needed, it is there with out having to turn it on.
It makes the out side of your house bright and makes it look nice.
Disadvantage
They cost a lot to buy compared to other electric powered light bulbs.
The light can only be used in a place where the sun will reach it as it will not charge if the sun does not hit the solar panel
The light will not work as will in short days like in winter. This is because the solar panels will not get enough light to charge.
The solar panels are sanative, they can brake.
