Physics paper 31 , (a death call)

[svenas]

answer was 9.33

wat u wrote for the voltage between X and Y?

 

[BurakBurak]

You are working a bit slower man the question answered 50 min ago

 

[BurakBurak]

2.4 v

 

[Hamzeh S]

guys expected thereshold for A* ?? 140-150 ? 150-160 ? 130-140 ?

 

[BurakBurak]

130-140

 

[bluefa1con]

wat u wrote for the voltage between X and Y?

6v since it was a parallel circuit

 

[kmkm20092008]

2.4 v

how did u get it? i got 2 wrong and if it is 2.4v so i got only 3 wrong so it is like 5 marks only
how did u get it 2.4v? i put it as 0v i think as it was for 1 mark so no working !!

 

[Hamzeh S]

so to be on the safe side you need to get 150 + for an A* ?

 

[Hamzeh S]

so to be on the safe side you need to get 150 + for A* ?

 

[bluefa1con]

how did u get it? i got 2 wrong and if it is 2.4v so i got only 3 wrong so it is like 5 marks only
how did u get it 2.4v? i put it as 0v i think as it was for 1 mark so no working !!

his answer is wrong

 

[kmkm20092008]

it is 6v i think , i wrote it 0 , but doesnt matter i still can get 70+/80 insha2 ALLAH

 

[BurakBurak]

Last question, A was resistor and B was LDR and for heat circuit A should be thermistor and B should be resistor, and component Y was a transistor

FOR HEAT IT SHOULD BE VICE VERSA

 

[Hamzeh S]

it is 6v i think , i wrote it 0 , but doesnt matter i still can get 70+/80 insha2 ALLAH

if its 6 v then the current would be equal to 3 since the resistance was 3! he told you the current was 0.8 and parralel have the same voltage so 2.4 up and 2.4 down so the current down was equal to 2.4/2 which was 1.2

 

[BurakBurak]

There was another resistence in series man How come I cant be 6 v

 

[Hamzeh S]

if its 6 v then the current would be equal to 3 since the resistance was 3! he told you the current was 0.8 and parralel have the same voltage so 2.4 up and 2.4 down so the current down was equal to 2.4/2 which was 1.2

sorry current = 2 * if its 6v but its not its 2.4 v

 

[BurakBurak]

I found 2.4v by solving the last question. Resistance was 1.8 ohms and the resistance of the parralel circuit is 1.2 ohms. From big resistance there need to be a big voltage so The main voltage divided as 2.4v and 3.6v

 

[bluefa1con]

if its 6 v then the current would be equal to 3 since the resistance was 3! he told you the current was 0.8 and parralel have the same voltage so 2.4 up and 2.4 down so the current down was equal to 2.4/2 which was 1.2

no
you had the current in one branch
you had the voltage which was same in both branches
current in one branch is not related to other
u had to find the current by V/R
so current in 2nd branch was 3A
the total resistance across parallel was 1.2 ohm
effective Resistance of circuit was 6/3.8=1.579 ohm
so u take the parallel's resistance out to get the other resistance 1.579-1.2= 0.379 ohm

 

[bluefa1con]

I found 2.4v by solving the last question. Resistance was 1.8 ohms and the resistance of the parralel circuit is 1.2 ohms. From big resistance there need to be a big voltage so The main voltage divided as 2.4v and 3.6v

you need to study parallel circuits and potential divider again
have a look at my post i hope you understand
V in parallel doesnt change

 

[Ahmedboombox]

Also the question about resistance and stuff
If I remember correctly, the voltage between X and Y was 2.4V
The resistance of R was 1.8 ohms
The current I3 was 1.2 A
I'm definitely sure of that, checked multiple times using different rules & formulas and nearly everyone in my class got same answers

At first i got 1.8 ohms as the resistance but then that is the total resistance of the circuit what i did was get the total resistance and the resistance of the parellel resistors then subtract both and i got a 1.1 ohms .

 

[Ahmedboombox]

Also the question about resistance and stuff
If I remember correctly, the voltage between X and Y was 2.4V
The resistance of R was 1.8 ohms
The current I3 was 1.2 A
I'm definitely sure of that, checked multiple times using different rules & formulas and nearly everyone in my class got same answers

At first i got 1.8 ohms as the resistance but then that is the total resistance of the circuit what i did was get the total resistance and the resistance of the parellel resistors then subtract both and i got a 1.1 ohms .