Whether or not it's in your exam board, it's worth knowing that: the reason that lot's of energy is lost at high current is because at high currents, the wires heat up and heat energy is transferred to the surroundings. We can either use a high current or high voltage to transfer the electricity (as P=IV). We just decided that high currents waste too much energy, so we choose to use very high voltages (meaning very low currents, as 'P' is constant in P=IV) .
This guy is a legend. Physics literally drops out of my head like my brain's a sieve, but this is making sense. I have mocks for all my sciences in two weeks, so thank you very much!!!!!!!
Watched this in lesson as really didn’t understand, thanks for this! I’ve recommended your channel to some of my friends and one of my friends has now subscribed to:)
I apologise for the incoming long comment, but why do we use low voltage to transmit electricity? My only thought it that, using V=IR, if we keep resistance constant and very low, whilst also increasing voltage we will get a very low current (with our already small resistance). Then, using P=(I^2)R, we will have a very low power output (which is thermal waste) because we will have a number
@@Freesciencelessons Thank you for the reply, there was a typo on my end, I meant to write high voltage (as I did later in the comment). I am just wondering, is the reason why we use high voltage because P=(I^2)R and a low current (due to high voltage) will reduce waste power output. Thank you.
Yes, if we use a high current to deliver electrical power, then power losses will be high as P = I^2R. If we use a high voltage instead to deliver the same power, then power losses will be lower as P = IV.
The power loss by the cables is given by P=IV or P=I2R. If we increase the current, then the power increases as a square of the current (from equation 2). However, if we increase the voltage, then power increases by a smaller proportion so less power loss in the cables at high voltage rather than high current.
I’m in Year 9 and in March I did some mock exams. On the morning of the science mock (which i was confident that i would fail despite finding out I passed) i knew nothing about the national grid (which spoiler alert didn’t appear). I tried to watch this but turned it off because of 2 reasons: 1. I couldn’t hear it through the traffic and I don’t bring earphones to school because I couldn’t be bothered 2. I remembered that I only live like 5 minutes away from school so I doubted that I wouldn’t finish the video before I got to school But still, ALL HAIL SHAUN DONNELLY! Also I need to state that my school made up the science exam whilst using questions from past papers. Also I got 36/60 on the paper for those wondering. I am still wondering how I passed the exam because I barely know a thing about science. Maybe it’s because I did WAY TOO MUCH REVISION FOR IT AND MY MUM FORCED ME TO DO IT (albeit in a kind loving way)
Hello sir, there is an equation given in the syllabus but I can't seem to find a video done by you covering it: potential difference across primary coil x current in primary coil = potential difference across secondary coil x current in secondary coil
watch one of these videos a day and copy down the information do the same for other subjects. this should take about an hour a day but it will be worth it to get top marks
because it would kill any appliance and be unsafe. If there was an exposed cable it would cause an arc because of the large potential difference compared to each with its 0V.
Because domestic appliances have fuses ranging to only 13A, so a current higher than that (which occurs until the step-down transformer) would cause this fuse to melt and the appliance would stop working Moreover, the voltage would be too high for the domestic appliances suitable only for 230V, causing them to stop working
The amount of heat energy wasted in the transmission cables is calculate from P = I2R (current squared x resistance) or P = VI (current x voltage) Looking at the first equation, if we increase the current in the power cables, then the power increases as a square of the current (in other words, a huge amount of energy is wasted in the cables). However, looking at the second equation, if we massively increase the voltage, then we can run a small current (for the same power) and the amount of heat energy wasted in the cables is much smaller.
The potential difference in the power cables is too large for homes. The step-down transformers are used to reduce the potential difference. I've made a separate video all about transformers th-cam.com/video/M9ytpIMB5d8/w-d-xo.html
Electricity suggests electrical charge and that is not lost in a wire. Some electrical energy is transferred to thermal energy in the wires so we can say that the energy has been transferred (or lost).
Is it true that if the current is lower, then thinner wires can be used for power transmission? I read it as an explanation for using lower current, just wanted to confirm.
This amazing human being used a step up transformer to raise my grades from a 3 to a 5. Thank you so much.
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@@kedusdawit4015 ?
@@kedusdawit4015 he improved, that’s all that matters.
HAHAHB GOOD ONE
if i get an 8 or a 9 this guy is the reason behind it.
L Star well did you
From June to November mocks I went from 6 to 7 in chemistry, 5 to 8 in physics and 6 to 9 in biology because of him
@@Marco-yz3hs damn, i cant get about 5, lets hope he does the same to me haha
DID YOU???????
@@sarathornton8325 chill out my guy
This channel is so much better than my physics teacher, thanks so much
Reuben Constantine lol
I agree
realest comment
Whether or not it's in your exam board, it's worth knowing that: the reason that lot's of energy is lost at high current is because at high currents, the wires heat up and heat energy is transferred to the surroundings. We can either use a high current or high voltage to transfer the electricity (as P=IV). We just decided that high currents waste too much energy, so we choose to use very high voltages (meaning very low currents, as 'P' is constant in P=IV) .
I was trying to understand this and ur comment help me, thank you
THANK YOU SO MUCH, YOU ARE A GENIUS MY FRIEND!!
You made this hell-sent topic understandable. I thank you.
Soon, this guys back will break from the weight of carrying 2020s GCSE students
my sister was supposed to take her GCSEs this year but now she can't
I'm in an internship right now and freesciencelessons is still teaching me. Thank you Sean, very cool!
This guy is a legend. Physics literally drops out of my head like my brain's a sieve, but this is making sense. I have mocks for all my sciences in two weeks, so thank you very much!!!!!!!
3 more days gl boys
sir u saved my grades for my mock gcse THANK YOU!!!
I went from a 5 , 4 in science to a 8 , 8 with just day before revision just because of this legend much love
This man explains it better than my actual physics teacher
this guy is literally a lifesaver
You just converted 4 of my (1 hour) physics lessons into like 5 minutes
fr tho teachers really be spending a whole week on like one topic
@@vlonesxm7884 it's like the UK is more inefficient at teaching than using carbon-free energy that isn't nuclear
@@vlonesxm7884 my teacher rn. spent 4 lessons on work done
lmao the test is in 30 mins and here i am
Wow,sir,you work so hard,makes me rethink about humanity when I see such persons
God bless. This amazing person is even better than my school teachers.
havent skipped a single ad just so this guy can get paid
Sir, YOU'RE AMAZING
From a 2-2 to a 7-7 in a year hopefully I clutch for the actual GCSE on Wednesday
what a comeback
how'd it go? @Jofish200
thank you sir. Today's the day.
I've got my gcses in a few weeks and I would just like to thank you for your amazing science videos which help me prepare well
Same
Same except I didn’t revise till now
This channel is so much interesting 😘😘
Like ur channel so much🤡
Thank you! Step-ups were on my paper
I don't think I should read my book as you make it very easy to understand ...Thanks a lot!!!
how does this guy make physics seem so easyy??? When my teacher explains stuff like this i get confused within the first 30 seconds of her speaking
who's here because of online school?
anyone?
Yep
Me
this video is focused on one picture... something I have never seen before...
Watched this in lesson as really didn’t understand, thanks for this!
I’ve recommended your channel to some of my friends and one of my friends has now subscribed to:)
I apologise for the incoming long comment, but why do we use low voltage to transmit electricity?
My only thought it that, using V=IR, if we keep resistance constant and very low, whilst also increasing voltage we will get a very low current (with our already small resistance). Then, using P=(I^2)R, we will have a very low power output (which is thermal waste) because we will have a number
Thanks for the comment. Remember though that we use a HIGH voltage to transmit electrical power over long distances.
@@Freesciencelessons Thank you for the reply, there was a typo on my end, I meant to write high voltage (as I did later in the comment). I am just wondering, is the reason why we use high voltage because P=(I^2)R and a low current (due to high voltage) will reduce waste power output. Thank you.
Yes, if we use a high current to deliver electrical power, then power losses will be high as P = I^2R. If we use a high voltage instead to deliver the same power, then power losses will be lower as P = IV.
@@Freesciencelessons Thank you very much!
whoever disliked this video better meet me outside. I just wanna talk -_-
Why would a higher potential difference mean there is less energy loss?
The power loss by the cables is given by P=IV or P=I2R.
If we increase the current, then the power increases as a square of the current (from equation 2). However, if we increase the voltage, then power increases by a smaller proportion so less power loss in the cables at high voltage rather than high current.
I’m in Year 9 and in March I did some mock exams. On the morning of the science mock (which i was confident that i would fail despite finding out I passed) i knew nothing about the national grid (which spoiler alert didn’t appear). I tried to watch this but turned it off because of 2 reasons:
1. I couldn’t hear it through the traffic and I don’t bring earphones to school because I couldn’t be bothered
2. I remembered that I only live like 5 minutes away from school so I doubted that I wouldn’t finish the video before I got to school
But still, ALL HAIL SHAUN DONNELLY!
Also I need to state that my school made up the science exam whilst using questions from past papers.
Also I got 36/60 on the paper for those wondering. I am still wondering how I passed the exam because I barely know a thing about science. Maybe it’s because I did WAY TOO MUCH REVISION FOR IT AND MY MUM FORCED ME TO DO IT (albeit in a kind loving way)
@@Wasteman365 is right
The Idiot it was all my mum. I didn’t even need half of it 😂
Great video helped me a lot on understanding the chapter
As V=IR, wouldnt a high voltage and a low current increase resistance and therefore increase energy transfer to surroundings?
Even better than my teachers
Hello sir, there is an equation given in the syllabus but I can't seem to find a video done by you covering it:
potential difference across primary coil x current in primary coil = potential difference across secondary coil x current in secondary coil
That's covered in the video "Transformers".
Is this all you need to know about the National Grid for higher questions ?
why is he not my school teacher?
I think he is
I think around 50% of our energy now comes from wind power. By the way, got physics paper 1 today.
I'm in yr10 going to y11 what should I be doing in the summer holidays pls help
watch one of these videos a day and copy down the information
do the same for other subjects.
this should take about an hour a day but it will be worth it to get top marks
enjoy it while it lasts mate
Abdur Rahman Enjoy it then pattern up in year 11
Abdur Rahman very late but you should have been enjoying yourself :)
Gaff it whilst u can
hi great videos
where do you get your revision workbook from?
i cant seem to find the link
believe it is being released once he finishes the entire spec, he is about halfway for all 3 sciences
I needed this
Are Transformers in physics , robots in disguise?
I'm sorry XD
No. But it would be cool if they were.
@@Freesciencelessons yes my guy
@Cara Wilson It was in one of my mocks, so I'd revise it anyway
why is it important to use a low voltage supply rather than using the mains supply directly
because it would kill any appliance and be unsafe. If there was an exposed cable it would cause an arc because of the large potential difference compared to each with its 0V.
Because domestic appliances have fuses ranging to only 13A, so a current higher than that (which occurs until the step-down transformer) would cause this fuse to melt and the appliance would stop working
Moreover, the voltage would be too high for the domestic appliances suitable only for 230V, causing them to stop working
how is this an efficient way of transferring energy?
Still don’t understand since voltage is the energy per coulomb wouldn’t making the voltage higher just mean that more energy is lost??
The amount of heat energy wasted in the transmission cables is calculate from
P = I2R (current squared x resistance)
or P = VI (current x voltage)
Looking at the first equation, if we increase the current in the power cables, then the power increases as a square of the current (in other words, a huge amount of energy is wasted in the cables).
However, looking at the second equation, if we massively increase the voltage, then we can run a small current (for the same power) and the amount of heat energy wasted in the cables is much smaller.
I actually get this topic now!
Is it power that is lost ? Or should you just say energy?
Energy, power is just the rate energy is transferred (over time).
great vid shaun buddy
2:58 is hands down the best part of this video
Hey sir will you ever make physics alevel videos
Anyone else here cramming videos the night before 😂
Yep.
Why step down transformers reduce the potential difference?
The potential difference in the power cables is too large for homes. The step-down transformers are used to reduce the potential difference. I've made a separate video all about transformers th-cam.com/video/M9ytpIMB5d8/w-d-xo.html
@@Freesciencelessons Thanks
How does more resistance mean heat energy lost?
resistance is caused by electrons colliding with atoms in the resistor. more atoms means more frequent collisions
so this causes heat to be released.
voice crack at 2:01
So *FiNaLlY*
Man stfu this guys a life saver stop picking up on small things he can't control at his big age
Great video thank you so much for your work :)
Why is saying less electricity is lost wrong/different from saying less energy is lost?
Electricity suggests electrical charge and that is not lost in a wire. Some electrical energy is transferred to thermal energy in the wires so we can say that the energy has been transferred (or lost).
GCSE squad give a like
Is it true that if the current is lower, then thinner wires can be used for power transmission? I read it as an explanation for using lower current, just wanted to confirm.
all nighter vibes
😁
Sick vid
شكرا ويعطيك العافية
my G bro thanks
No problem. Thanks for the comment.
You should be watching the video and revising not reading the comments
Got me😂 but I usually go in comments to help people who don't understand things I understand, as Dr Donnelly can't reply to everyone.
Helped a bunch ! Thanks
Litteraly have my exam in an 2 hours 😭😭
I have. Physic exam in 13 hours and I need to go to sleep in 2 hours
drop some merch
Buy his revision books, they're his merch and they're worth it.
My g for the vid
Mans got high iq
My exam is in 45 minutes 25 may 2023
thanks g
I love u
'thank you, next' video!
Dem 36 haters...
Thank you
video helped
Thank you sir
My gggggg
Ggg