I will be really grateful if someone can explain this to me. A battery connected in series with a resistor R of resistance 5.0 Ω. The electromotive force (e.m.f.) of the battery is 9.0 V and the internal resistance is r.
The potential difference (p.d.) across the battery terminals is 6.9 V.
Calculate the current in the circuit.

Question

I will be really grateful if someone can explain this to me. A battery connected in series with a resistor R of resistance 5.0 Ω. The electromotive force (e.m.f.) of the battery is 9.0 V and the internal resistance is r.
The potential difference (p.d.) across the battery terminals is 6.9 V.
Calculate the current in the circuit.

anonymous · Answer

Now the formula I used was E=V+Vr where V= terminal p.d and Vr=p.d across battery

9=6.9+I(5)
I= 0.42A 

But apparently the answer is incorrect. Why? @experimentX  @ganeshie8

sidsiddhartha · Answer

but it seems correct

sidsiddhartha · Answer

E-ir=IR

anonymous · Answer

No, the answer is 1.38 A.

anonymous · Answer

I know. That's what is confusing me. The formula is right, then why is the answer incorrect?

sidsiddhartha · Answer

|dw:1398454706860:dw|
that's the ckt is'nt it