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10 Dec 2025
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Understanding Potential Dividers in N5 Physics Electricity
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Understanding Voltage Dividers
Ever wondered why your phone's screen dims automatically? Voltage dividers are the answer! When you connect two or more resistors in series, the supply voltage doesn't just disappear - it cleverly splits across each resistor.
The key principle is simple: voltage splits based on resistance values. If you've got two identical 500 Ω resistors connected to a 12 V battery, each resistor gets exactly 6 V. Think of it like sharing a pizza equally between two equally hungry friends.
But here's where it gets interesting - when resistors have different values, the voltage split becomes unequal. A 10 kΩ resistor will grab more voltage than a 5 kΩ resistor because the greater the resistance, the greater the voltage across it. Remember: V ∝ R from Ohm's law .
Quick Check: In a voltage divider, the resistor with the highest resistance always gets the biggest share of the supply voltage!
Calculating Voltage Splits - Method 1
When you know the supply voltage and both resistance values, you've got a straightforward formula to work with. This is probably the most common type of question you'll see in exams.
For any resistor in the circuit, use this voltage divider equation: V₂ = × Vs. The pattern is simple - put your target resistor on top of the fraction, and the total resistance on the bottom.
Let's say you've got a 12 V supply with a 3 kΩ and 6 kΩ resistor in series. The voltage across the 6 kΩ resistor would be: V = (6000/(3000 + 6000)) × 12 = 8 V. The remaining 4 V appears across the 3 kΩ resistor.
Pro Tip: Always check your answers add up to the supply voltage - it's a foolproof way to spot calculation errors!
Calculating Voltage Splits - Method 2
Sometimes exam questions throw you a curveball by not giving you the supply voltage directly. Don't panic - there's still a way forward using the voltage ratio method.
When you know both resistances and the voltage across just one resistor, use this elegant relationship: V₁/V₂ = R₁/R₂. This formula shows that voltage ratios equal resistance ratios in series circuits.
Imagine you've got a 2 kΩ and 8 kΩ resistor in series, and you know there's 3 V across the 2 kΩ resistor. Using the ratio: 3/V₂ = 2000/8000, so V₂ = 12 V. The total supply voltage must be 15 V.
Exam Strategy: This ratio method is perfect for those tricky questions where the supply voltage is hidden - you can often work backwards to find it!
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In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding Potential Dividers in N5 Physics Electricity
Voltage dividers are everywhere in electronics - from the volume control on your headphones to the brightness sensor on your phone. Understanding how voltage splits across resistors in series circuits is crucial for A-level Physics and will help you tackle... Show more
Understanding Voltage Dividers
Ever wondered why your phone's screen dims automatically? Voltage dividers are the answer! When you connect two or more resistors in series, the supply voltage doesn't just disappear - it cleverly splits across each resistor.
The key principle is simple: voltage splits based on resistance values. If you've got two identical 500 Ω resistors connected to a 12 V battery, each resistor gets exactly 6 V. Think of it like sharing a pizza equally between two equally hungry friends.
But here's where it gets interesting - when resistors have different values, the voltage split becomes unequal. A 10 kΩ resistor will grab more voltage than a 5 kΩ resistor because the greater the resistance, the greater the voltage across it. Remember: V ∝ R from Ohm's law .
Quick Check: In a voltage divider, the resistor with the highest resistance always gets the biggest share of the supply voltage!
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Calculating Voltage Splits - Method 1
When you know the supply voltage and both resistance values, you've got a straightforward formula to work with. This is probably the most common type of question you'll see in exams.
For any resistor in the circuit, use this voltage divider equation: V₂ = × Vs. The pattern is simple - put your target resistor on top of the fraction, and the total resistance on the bottom.
Let's say you've got a 12 V supply with a 3 kΩ and 6 kΩ resistor in series. The voltage across the 6 kΩ resistor would be: V = (6000/(3000 + 6000)) × 12 = 8 V. The remaining 4 V appears across the 3 kΩ resistor.
Pro Tip: Always check your answers add up to the supply voltage - it's a foolproof way to spot calculation errors!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Calculating Voltage Splits - Method 2
Sometimes exam questions throw you a curveball by not giving you the supply voltage directly. Don't panic - there's still a way forward using the voltage ratio method.
When you know both resistances and the voltage across just one resistor, use this elegant relationship: V₁/V₂ = R₁/R₂. This formula shows that voltage ratios equal resistance ratios in series circuits.
Imagine you've got a 2 kΩ and 8 kΩ resistor in series, and you know there's 3 V across the 2 kΩ resistor. Using the ratio: 3/V₂ = 2000/8000, so V₂ = 12 V. The total supply voltage must be 15 V.
Exam Strategy: This ratio method is perfect for those tricky questions where the supply voltage is hidden - you can often work backwards to find it!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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4.8/5
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user