# energy efficiency

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#1
the table gives data about two types of light bulb people may use in their homes.

type of light bulb energy efficiency cost of one light bulb average lifetime in hours
halogen 10% £1.95 2000
light emitting
diode (LED) 32% £11.70 3600

both types of light bulbs produce the same amount of light
Evaluate, in terms of cost and energy efficiency, the use of the two types of light bulb
You must compare both types of light bulbs and conclude with which bulb is better
(6 marks )

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2 years ago
#2
I'd essentially talk about the differences between the 2 types of bulbs, so the advantages and disadvantages of both. Then I'd make a conclusion based on what I think would be the best.

The kinds of things you might say could be:
It is much cheaper to buy an individual halogen bulb, in comparison to the LED bulb.
However, the lifetime of an LED is much higher (I remember seeing the question last year when doing my GCSEs, I think the lifetime of the LED was 36,000 hours, not 3600. Might be wrong though).
The LED bulb is also more efficient than the halogen bulb, meaning there is less energy loss (through heat when current flows through the bulb). This means the LED will have a lower running cost, and will require a lower input of energy to provide the same light output.

You also might want to include figures from the table in your answer, doesn't look like it's required in this answer but on some, it'll say refer to the table or diagram, then you'll lose marks if you don't include some information given, such as figures. Just make sure to read the question carefully.

Then you'd need to come to a conclusion on which is better, I'd go for the LED and then justify it, saying that even though the original price is higher, it would last a lot longer and be much more efficient, meaning overall, it is likely the price would be lower.

You'll be quite lucky if you get a 6-marker like that in the exam, since it doesn't require too much application of knowledge. I'd say that if you do get an evaluation question (can't remember if there was one in the exam I did in June) it'll give you some information, but there'll also be a few marks from applying your own understanding. An example of this is evaluating two types of power, such as wind power vs nuclear. It might give you some information in the question but you'd probably also be expected to include some advantages and disadvantages of your own.

Hope this helps. If there's any more questions you need help on, I can try and help with those.
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