# Physics definition questions

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Thread starter 2 years ago
#1
Hey guys please may you tell me how to answer questions that ask you how to define things like the volt or Newton? I'm confused about when to define things like
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2 years ago
#2
just look at the equation. for example for volt. V=W/Q. so volt is just the work done per charge
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Thread starter 2 years ago
#3
Thanks but how do I know when to say like 1 newton is the force required to accelerate a 1kg object by 1ms-2 or something like e.m.f. is the work done on electrons per unit of charge through a component in a circuit
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2 years ago
#4
(Original post by Freedom physics)
Thanks but how do I know when to say like 1 newton is the force required to accelerate a 1kg object by 1ms-2 or something like e.m.f. is the work done on electrons per unit of charge through a component in a circuit
i have never seen a question like that in any a level physics exam, so dont worry too much. but in case you care, you can simply plug 1 in(for most equation). so F=ma. if you make m=1 and a=1. then f=1. so 1 newton is the force required to accelerate a mass of 1kg
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Thread starter 2 years ago
#5
A question says "define potential difference", how would I know to say "1 volt is 1 joule of work done on the electrons passing through a component in a circuit per 1 coulomb of charge" instead of "potential difference is the work done on electrons passing through a component in a circuit per unit charge"? 🙂, plus, why wouldn't I say "potential difference is the current flowing through a component in a circuit for every ohm of resistance of the component"? 😄
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2 years ago
#6
(Original post by Freedom physics)
A question says "define potential difference", how would I know to say "1 volt is 1 joule of work done on the electrons passing through a component in a circuit per 1 coulomb of charge" instead of "potential difference is the work done on electrons passing through a component in a circuit per unit charge"? 🙂, plus, why wouldn't I say "potential difference is the current flowing through a component in a circuit for every ohm of resistance of the component"? 😄
Look to see if they are asking about a quantity or a unit. For example;

- if you are asked to define potential difference, that is a quantity, so your answer should not involve particular units, just other quantities. "Potential difference is the energy transferred from electrical to other forms per unit charge."

- if you are asked to define a unit, you need to be specific about exactly how to determine the size of the unit. "One volt is the potential difference (or emf) when one joule of energy is transformed per coulomb of charge."
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Thread starter 2 years ago
#7
Thanks! This helps a lot!! 😂, are you using g board? 😄
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2 years ago
#8
(Original post by Freedom physics)
Thanks! This helps a lot!! 😂, are you using g board? 😄
I don't know what that is, sorry.
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Thread starter 1 year ago
#9
I'm putting your answer into my exam notes, thank you! 😄
(Original post by Pangol)
Look to see if they are asking about a quantity or a unit. For example;

- if you are asked to define potential difference, that is a quantity, so your answer should not involve particular units, just other quantities. "Potential difference is the energy transferred from electrical to other forms per unit charge."

- if you are asked to define a unit, you need to be specific about exactly how to determine the size of the unit. "One volt is the potential difference (or emf) when one joule of energy is transformed per coulomb of charge."
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1 year ago
#10
(Original post by Freedom physics)
I'm putting your answer into my exam notes, thank you! 😄
Glad it was still useful one year on...
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