# Homework Help: What is the current in this circuits?

1. Oct 29, 2016

### PhysicsNewbie321

1. The problem statement, all variables and given/known data

2. Relevant equations
Ohm's Law : V = IR, Eel = VIt , Vt=ItRt , Q=It

3. The attempt at a solution

I tried to do the first question letter a

I=? I= V/R
R=3 ohms I= 6/3
V=6V I=2A

i dont know how to continue the others :/

2. Oct 29, 2016

### Merlin3189

So far, so good, so long as you know what it is that you have worked out.

Your final line says, V=6V I=2A so now you know V,I and R for the 6Ω resistor

So now, what do you know about the 3Ω resistor?

3. Oct 29, 2016

### PhysicsNewbie321

I dont know if I can work out b) without any given volts in the 2nd 1ohm resistor

4. Oct 29, 2016

### Staff: Mentor

What type of circuit is depicted? Is it series-connected or parallel-connected?

5. Oct 29, 2016

### Merlin3189

But you haven't said what you DO know about it!
I'll give you a start. You know R is 1Ω. Now, can you tell me what I or V is? (without doing any calculation yet.)

If you say you know neither I nor V, you could try drawing on the circuit, or think about gneill's question,. .Because you DO know one of them! And you only need 2 out of 3 to work out the other.

6. Oct 30, 2016

### PhysicsNewbie321

its connected in series meaning voltage is divided among components.

V - volts , I - current.

I dont know the volts of the battery

7. Oct 30, 2016

### cnh1995

You need not know that.
What else does that mean? What about the current through the series components?

8. Oct 30, 2016

### PhysicsNewbie321

series same current

9. Oct 30, 2016

### Staff: Mentor

So then, what is the current through the 1 Ω resistor?

10. Oct 30, 2016

### PhysicsNewbie321

2A?

11. Oct 30, 2016

### Staff: Mentor

Yes. It's a series circuit so there is only one current.

12. Oct 30, 2016

### PhysicsNewbie321

thanks

13. Oct 30, 2016

### cnh1995

Yes. So what is the voltage across the 1 ohm resistor?

14. Oct 30, 2016

### PhysicsNewbie321

for b) 2A

c) v=Ir
2x1=2volts

15. Oct 30, 2016

### cnh1995

Yes. Now you have sufficient information to calculate the p.d. across the battery.

16. Oct 31, 2016

### PhysicsNewbie321

for d) is it 6V + 2V = 8V?

e) each cell has 2v?

17. Oct 31, 2016

### cnh1995

Yes.

18. Oct 31, 2016

### PhysicsNewbie321

Thanks thats a question done.

For the next problem,

a) 1.5x4 = 6V
b)
V?
R=6ohm
I= 1? (v/ohm,6/6)

6x1=6V?

c) 1A?

thanks alot man

19. Oct 31, 2016

### cnh1995

Yes.

20. Oct 31, 2016

### PhysicsNewbie321

d)

v=?
r=3ohm
i=2a(6/3)

v=ir 2x3 = 6V?

e)2A?

but how come can both be 6V when its a 6V battery?

21. Oct 31, 2016

### cnh1995

What can you say about the voltage across two parallel components?

22. Oct 31, 2016

### PhysicsNewbie321

a i see constant pd

thanks

23. Oct 31, 2016

### PhysicsNewbie321

e) 2A

f) 2a+1a = 3A

g) 1/6 + 1/3 = 1/2 = 2A?

@cnh1995

Last edited: Oct 31, 2016
24. Oct 31, 2016

### cnh1995

Yes.

25. Oct 31, 2016

### PhysicsNewbie321

my mistake.. its ohms.

thanks for all your help !!