UNOFFICIAL MARKSCHEME!~AQA GCSE Physics Unit 2 25th Janurary NEW SPEC

Original post by ali_d123

I have this too. Jesus the mock was hard. I have nearly finished watchign all of mygcsescience p2 videos!

I dont feel that website helps because on my speakers it isnt loud enough... :mad:

Reply 61

The_Dragonborn

I'm doing this exam too!

Not looking forward to it...

Reply 62

Original post by lolface32

Maths by far, so easy!

hmmm, fair enough. what topics do you think will come up?

Reply 63

Original post by lolface32

Because V=IR, so R=V/I. The higher the value of I the lower the value of R? I did not understand this question and doubt there is anything like this on our spec? If total resistance= sum of resistors, how can it be less than the resistance of each component?

wait, i saw a question like that in my book, lemme just check again. maybe i didnt write it out right.

Reply 64

Original post by pinkgorilla

the life cycle of stars is annoying me... and i used to like stars :/

LOL, we cant just casually gaze at them forever.. :biggrin:

Reply 65

Original post by Ammy97

LIFE SAVER!!! Thanks so much :biggrin:

I second that :biggrin:

Reply 66

Original post by pinkgorilla

hmmm, fair enough. what topics do you think will come up?

I genuinely have no idea! It is not as predictable as Biology was for some weird reason. I hope it asks us to correct or construct a circuit though with maybe a little emphasis on momentum, and little on mains! :angry:

Reply 67

Arshii

Original post by pinkgorilla

Hehe, I realised that after i posted it . :smile:

Yeh, sounds really good.

In a parallel:
- the potential difference is equal to the potential difference of the supply through each branch
- the current is shared out between the branches (in proportion to the resistance pf the components, right?)

In a series:
- the potential difference is shared out between the components in proportion to their resistance
- the current is the same for each component

Why is the total resistance of a parallel circuit lower than the resistance of each component?

huhh?

isn't the total resistance HIGHER than the resistance of each component... because they add together making the total resistance higher..?
I really don't know this one..? Answer please.?

Reply 68

Original post by The_Dragonborn

I'm doing this exam too!

Not looking forward to it...

Your telling me, im dreading this, tomorrow feels like judgement day

Reply 69

Original post by Arshii

huhh?

isn't the total resistance HIGHER than the resistance of each component... because they add together making the total resistance higher..?
I really don't know this one..? Answer please.?

That was exactly what I thought,
but then asked my cousin(doing a degree in physics at Oxford :biggrin:

) and he told me to remember1/R = 1/R1 + 1/R2?
Also think of it as, R=V/I and so the higher the current the less the resistance!

(edited 11 years ago)

Reply 70

Original post by lolface32

Because V=IR, so R=V/I. The higher the value of I the lower the value of R? I did not understand this question and doubt there is anything like this on our spec? If total resistance= sum of resistors, how can it be less than the resistance of each component?

Oh okay, I found it in my book now. Basically, as you add more components in a parallel circuit there would be more alternative ways for the current to flow. This means that the overall current will be higher, and as Ohm's Law states that for current to increase, resistance has to decrease (provided that the potential difference stays the same) it shows that the overall resistance will decrease.

I used to get so confused on this but then my teacher explained it to me last week :biggrin:

(edited 11 years ago)

Reply 71

Arshii

Original post by lolface32

lol, that was my answer! Good to know I at least knew what to do.

What kind of questions do you prefer. Maths orientated or more wordy type?

I think maths orientated to be honest - even though I really hate maths. But, in physics I think its much simpler and sometimes straightforward whereas, with wordy questions it can get pretty complicated - like having to mention specific key words.. Sometimes it can be alright but, sometimes you're just look at the question... what the heck? LOL! :biggrin:

What about you? Maths or wordy? :smile:

Reply 72

Original post by Arshii

huhh?

isn't the total resistance HIGHER than the resistance of each component... because they add together making the total resistance higher..?
I really don't know this one..? Answer please.?

thats for series circuits because current stays the same for each component , i put the explanation above :biggrin:

Reply 73

Original post by pinkgorilla

Oh okay, I found it in my book now. Basically, as you add more components in a parallel circuit there would be more alternative ways for the current to flow. This means that the overall current will be higher, and as Ohm's Law states that for current to increase, resistance has to decrease (provided that the potential difference stays the same) it shows that the overall resistance will decrease.

I used to get so confused on this but then my teacher explained it to me last week :biggrin:

What book are you using if you don't mind me asking? :smile:

Reply 74