GCSE - Electricity question

Hi,

I was doing a past GCSE paper and I got stuck on this question to do with electricity, so I was wondering if anyone would be able to help.

'When the voltage across the bulb falls to half, the current through the bulb falls by less than half. Why is this?'

Thanks!

Reply 1

mackin boi

1

u got me stumped and i do A Level fysix...lol

Reply 2

m:)ckel

14

Lol, same.
I dunno, maybe it's like a more practical reason. Such as resistance across the bulb increasing, as it heats up. Since I = V/R, a higher R will yield a smaller I...

Reply 3

andyj72

2

lol, same here too. :confused:

Err... V=IR :rolleyes:

Do u think this makes sense.

if the voltage is reduced, it is doing less work against the charge particles flowing in the circuit. because the harder the voltage is the greater the internal energy which will further oppose the movement of charge particles. reducing the voltage will mean that there is less internal energy(heat) created therefore the current wont decrease as much.

Correct anyone??????

Reply 4

andyj72

2

mockel

Lol, same.
I dunno, maybe it's like a more practical reason. Such as resistance across the bulb increasing, as it heats up. Since I = V/R, a higher R will yield a smaller I...

hey mockel, just read urs and its kinda the same as mine, lol

Reply 5

SinghFello

2

andyj72

lol, same here too. :confused:

Err... V=IR :rolleyes:

Do u think this makes sense.

if the voltage is reduced, it is doing less work against the charge particles flowing in the circuit. because the harder the voltage is the greater the internal energy which will further oppose the movement of charge particles. reducing the voltage will mean that there is less internal energy(heat) created therefore the current wont decrease as much.

Correct anyone??????

Thats right, but waaaaaay to much depth for GCSE.

Reply 6

andyj72

2

SinghFello

Thats right, but waaaaaay to much depth for GCSE.

lol, yes. i will try to explain in in brief. :biggrin:

u can c my luv of phy 2 - electricity and thermal phy

Reply 7

andyj72

2

sweet_gurl, i will try to simplify the explantion.

Basically,

if the voltage is reduced, it is doing less work against the charge particles flowing in the circuit. this is because the higher the voltage, the heat build up is more , more particles are moving towards the resistance heating it up. so reducing the voltage means that the components will not heat up as much.(increase in heat reduces the flow of charge). so more current will not decrease as much. :smile:

.

hope this helps. if u can understand this u can c if u can make sense of what i said previously. the examiner will be impressed and give u full marks for the question and even a bonus mark :biggrin:

how many marks was this question?

Reply 8

sweet_gurl

OP

4

Thanks for your help everyone! andyj72, thanks for the explanations, I was able to understand your answer, and so the question makes more sense now! I think the question was only worth around 3 marks, so not that much. :smile:

Reply 9

andyj72

2

sweet_gurl

Thanks for your help everyone! andyj72, thanks for the explanations, I was able to understand your answer, and so the question makes more sense now! I think the question was only worth around 3 marks, so not that much. :smile:

ok, no problemo :wink:

3 marks is a lot, then again there is a lot of detail to written about it.

now that u understand it, things maybe clearer when u study A-level phy if ur going too :p:

GCSE - Electricity question

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