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PHY1H (OLD SPEC) Unit 1 AQA GCSE

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Reply 80
Original post by Nikhil_m
ah mate, i mentioned its not ionising lol, so if u eat it u wont be harmed. and short half life, but nothing about penetrating boxes :frown:


Lol that was such a random question. I just treated it like medical tracing like in kidneys :frown:
Reply 81
Anyone get 5 years for the payback time?
Reply 82
Original post by Aidanb90
Anyone get 5 years for the payback time?


Yes, but I left it at 60 months.. Do you think that's okay?
Reply 83
Original post by clare1111
Yes, but I left it at 60 months.. Do you think that's okay?


Yeah I think, because they didn't give you the unit. :smile:
Reply 84
Original post by Aidanb90
Yeah I think, because they didn't give you the unit. :smile:


Thank you!
Reply 85
Original post by maxtate
Conduction/convection, half-life, satellites, EM spectrum (microwaves), red shift, forgot the rest 8-)


please try and remember the rest :smile: what kind of questions were there? and how many questions? :biggrin:
Reply 86
Original post by R.P.Everything.
I'm pretty sure the radioactive material isn't put in the food itself; it's put over the food and radiation is released in beams to irradiate the food. Besides, from chemistry, anything with technetium in is highly toxic, so I doubt they would actually spray the food with that.

Can someone else confirm what the right answer is?


I put Colbalt reason being:

NEally all the food has a LONG-SHELF LIFE and if it was tech 99 the food will have a short shelf-life since bacteria can penitrate. Plus Wikipedia says it
Reply 87
Original post by Aidanb90
It was technetium with 6 hour half-life. Penetrates the food but decays fast so food is safe.

I put ethical and economical. It was about money and ethical because is it right to be possibly endangering children with long term microwave exposure.


same put ethical and eco :smile:
Your not ment to know that though so thinking about it why is it not tech 99. You want radiation to be inthe food for a short amount of time just enough to kill bacteria but as not to harm you

This was posted from The Student Room's Android App on my HTC Sensation XL with Beats Audio X315e
Reply 89
I think we'll both get the mark, but it depends what you write for the reason :smile: Cuz you cud say both tbh lol
Reply 90
And guys what u get for independent variable cuz there were 2 lool i put position of head :/
Reply 91
Original post by MichelleQ
please try and remember the rest :smile: what kind of questions were there? and how many questions? :biggrin:


cant u remember?
Reply 92
Original post by maxtate
And guys what u get for independent variable cuz there were 2 lool i put position of head :/


I think it was the type of ground, the direction was more for reliability like a different type of the same test.

And I think we are right for the the ethical and economical one. It has to be that because the other two had environmental in them. I don't think microwaves from masts is an environmental issue.
Reply 93
is position of the dummy independent?
Reply 94
and the payback time was a few months
Reply 95
Hi everyone, I have tried to make an unofficial mark scheme based on the questions and answers I can remember. I do apologise in advance if the questions and answers in the correct order. Feel free to correct in any of my answers which may be wrong or add on any questions which I may have missed

What is meant by renewable? (1)
It is replaced faster than it is used

Suggest one reason why the farmers were given their own biogas (can't exactly remember) (1)
The farmers can use it to their own personal preference and burn the methane produced by their farm animals.

Why is biogas better than solar cells? (2)
It is more reliable
It is faster
(Other answers may be accepted as well)

Which type of UV Radiation is not harmful? (1)
I drew a circle around the one where the arrow didn't go past the ozone layer (I think it was UVC)

Explain your answer (1)
It doesn't go through or penetrate through the ozone layer unlike the other 2 types of UV Radiation.

What effect would decreasing the thickness of the ozone layer have on people's health? (2)
It would be more harmful because the UV Radiation would be able to pass through the ozone layer (I can't remember what else I put)

What was the independent variable in the dummy investigation? (1)
The dummy's direction (facing the sun and not facing the sun)

How could the reliability of the results be improved? (1)
Do more repeats.

What is a better reflector of UV, sand or snow? (2)
Sand, it had the lowest UV absorbed, therefore it reflected most of it.

Are the manufacturer's claims right about 100% UV Protection? (2)
No, the UV is not 0 when the sunglasses are worn, and when the wavelength is quite low (280-320), the UV rises and falls, it isn't consistent. (There are also other things to put down, this may be an allowable answer)

Draw an analogue and digital signal (2)
Correctly drawn diagrams.

Suggest one reason why parents are against the use of mobile phones (1)
They think that there may be harmful long-term effects of microwave radiation.

What is the phone situation? (1)
Economic and social issue

Question on red-shift and galaxies. (sorry, I can't exactly remember) (1)
Galaxies are moving away from us and the universe is expanding.

Fill in the missing gap (1)
Origins (of the Universe)

How is an optical telescope better than ? telescope? (1)
It is clearer

Explain why (1)
Light is not scattered in space, whereas light is scattered by the Earth's atmosphere.

Which radioisotope would be the best for the food (1)
Technetium-99 (maybe incorrect spelling)

Explain your answer (2)
It has gamma which can penetrate through the food and it has the shortest half-life, therefore the shortest decay (NOT SURE IF I GOT THIS RIGHT)

Explain what happens in convection in the house (3)
The particles are heated, and they move faster, the air expands, also the heat rises through the air. (I can't remember what else I put)

Explain in terms of particles in a metal, the process of conduction (2/3) (Can't exactly remember how many marks this was worth)
The free electrons in the metal gain thermal energy, they carry, transfer and pass on the energy to the fixed particles in the metal. (Unsure about this)

Suggest one advantage of having no insulation by the chimney (1)
The chimney is warmer

Why is it important that the radiation is carried about by an independent group of scientists? (1)
To avoid bias

Suggest one reason why people may not want to eat radiated foods? (1)
They are unsure about the long-term consequences of eating radiated foods.

From the data in the table, can it be concluded that irradiated foods contain more vitamins than radiated foods? (2/3)
No, only 40% of the type of vitamins are higher in the irradiated foods than the radiated foods. Only 1kg of chicken was used, vitamin content may be different for other foods. The experiment was only done once. Some of the vitamin content of certain vitamins is higher in radiated foods than irradiated foods and vice versa, the pattern of different types of vitamin content is inconsisent.

Suggest one reason why people should know if their food is radiated or not? (1)
They may not want to eat radiated food.

What is a beta particle and where is it emitted from? (2)
It is an electron emitted from the nucleus.

How long would it take for the radioisotope to get to 75 count rates (2)
90 years

How much energy is useful in the device with an efficiency of 0.95? (2)
7.6J

What happens to the wasted energy (2)
It is transferred to the surroundings

Use the kilowatt hour equation to help you find out the time (2/3)
200 hours (may have got this wrong, but I showed my working, so hopefully I may get a mark)

I found this exam a little bit different from all of the past papers. There were some tricky questions in there, but it wasn't drastically bad. The percentage to get an A* in Physics Unit 1 on average is approximately 65% (29-30/45). The highest it has ever been to get an A* in Physics is 71% and the lowest it has ever been is 60%. I don't really see the grade boundaries exceeding 31 for an A*. My mark scheme is unofficial and may have errors in it, so please don't take my final answers for granted.
:rolleyes:
Reply 96
Hi everyone, I have tried to make an unofficial mark scheme based on the questions and answers I can remember. I do apologise in advance if the questions and answers in the correct order. Feel free to correct in any of my answers which may be wrong or add on any questions which I may have missed

What is meant by renewable? (1)
It is replaced faster than it is used

Suggest one reason why the farmers were given their own biogas (can't exactly remember) (1)
The farmers can use it to their own personal preference and burn the methane produced by their farm animals.

Why is biogas better than solar cells? (2)
It is more reliable
It is faster
(Other answers may be accepted as well)

Which type of UV Radiation is not harmful? (1)
I drew a circle around the one where the arrow didn't go past the ozone layer (I think it was UVC)

Explain your answer (1)
It doesn't go through or penetrate through the ozone layer unlike the other 2 types of UV Radiation.

What effect would decreasing the thickness of the ozone layer have on people's health? (2)
It would be more harmful because the UV Radiation would be able to pass through the ozone layer (I can't remember what else I put)

What was the independent variable in the dummy investigation? (1)
The dummy's direction (facing the sun and not facing the sun)

How could the reliability of the results be improved? (1)
Do more repeats.

What is a better reflector of UV, sand or snow? (2)
Sand, it had the lowest UV absorbed, therefore it reflected most of it.

Are the manufacturer's claims right about 100% UV Protection? (2)
No, the UV is not 0 when the sunglasses are worn, and when the wavelength is quite low (280-320), the UV rises and falls, it isn't consistent. (There are also other things to put down, this may be an allowable answer)

Draw an analogue and digital signal (2)
Correctly drawn diagrams.

Suggest one reason why parents are against the use of mobile phones (1)
They think that there may be harmful long-term effects of microwave radiation.

What is the phone situation? (1)
Economic and social issue

Question on red-shift and galaxies. (sorry, I can't exactly remember) (1)
Galaxies are moving away from us and the universe is expanding.

Fill in the missing gap (1)
Origins (of the Universe)

How is an optical telescope better than ? telescope? (1)
It is clearer

Explain why (1)
Light is not scattered in space, whereas light is scattered by the Earth's atmosphere.

Which radioisotope would be the best for the food (1)
Technetium-99 (maybe incorrect spelling)

Explain your answer (2)
It has gamma which can penetrate through the food and it has the shortest half-life, therefore the shortest decay (NOT SURE IF I GOT THIS RIGHT)

Explain what happens in convection in the house (3)
The particles are heated, and they move faster, the air expands, also the heat rises through the air. (I can't remember what else I put)

Explain in terms of particles in a metal, the process of conduction (2/3) (Can't exactly remember how many marks this was worth)
The free electrons in the metal gain thermal energy, they carry, transfer and pass on the energy to the fixed particles in the metal. (Unsure about this)

Suggest one advantage of having no insulation by the chimney (1)
The chimney is warmer

Why is it important that the radiation is carried about by an independent group of scientists? (1)
To avoid bias

Suggest one reason why people may not want to eat radiated foods? (1)
They are unsure about the long-term consequences of eating radiated foods.

From the data in the table, can it be concluded that irradiated foods contain more vitamins than radiated foods? (2/3)
No, only 40% of the type of vitamins are higher in the irradiated foods than the radiated foods. Only 1kg of chicken was used, vitamin content may be different for other foods. The experiment was only done once. Some of the vitamin content of certain vitamins is higher in radiated foods than irradiated foods and vice versa, the pattern of different types of vitamin content is inconsisent.

Suggest one reason why people should know if their food is radiated or not? (1)
They may not want to eat radiated food.

What is a beta particle and where is it emitted from? (2)
It is an electron emitted from the nucleus.

How long would it take for the radioisotope to get to 75 count rates (2)
90 years

How much energy is useful in the device with an efficiency of 0.95? (2)
7.6J

What happens to the wasted energy (2)
It is transferred to the surroundings

Use the kilowatt hour equation to help you find out the time (2/3)
200 hours (may have got this wrong, but I showed my working, so hopefully I may get a mark)

I found this exam a little bit different from all of the past papers. There were some tricky questions in there, but it wasn't drastically bad. The percentage to get an A* in Physics Unit 1 on average is approximately 65% (29-30/45). The highest it has ever been to get an A* in Physics is 71% and the lowest it has ever been is 60%. I don't really see the grade boundaries exceeding 31 for an A*. My mark scheme is unofficial and may have errors in it, so please don't take my final answers for granted.
:rolleyes:
Reply 97
I'm so annoyed because I put technetium-99 but it was cobalt-60 because the gamma radiation isn't actually absorbed by the food, just transmitted so the food doesn't become radioactive, the bacteria is simply killed in its path. The half-life therefore needs to be long to prevent having to replace the source so often :frown:
Original post by Student95
I'm so annoyed because I put technetium-99 but it was cobalt-60 because the gamma radiation isn't actually absorbed by the food, just transmitted so the food doesn't become radioactive, the bacteria is simply killed in its path. The half-life therefore needs to be long to prevent having to replace the source so often :frown:


You said there the bacteria is simply killed... Thats what you want
Reply 99
Best physics exam so far... definitely a B, tiny bit of luck and easily an A for me!

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