Question : Copper and iron wires of same length and diameter are in series connected across a battery. The resistivity of copper is about one sixth of that of iron. If E1 and E2 are electric fields in the copper and iron wires respectively, then which one of the following is correct?
a) E1<E2
b) E1=E2, is not equal to 0.
c) E1>E2
d) E1=E2=0
Doubt by Khuspreet
Solution :
We know,
E = jρ
E = (I/A)ρ
As per the given question both I (Series Connection) and A (Diameter is same) are same.
E = jρ
E = (I/A)ρ
As per the given question both I (Series Connection) and A (Diameter is same) are same.
So
E∝ρ
ρc=ρi/6 (Given)
E∝ρ
ρc=ρi/6 (Given)
Ec=Ei/6
E1=E2/6
6E1=E2
Clearly,
E1<E2
E1=E2/6
6E1=E2
Clearly,
E1<E2
Hence, a) is the correct answer.
