Two wires A and B are made of the same material and have the same diameter.Wire A is twice as long as wire B.If each wire has the same potential difference across its ends,which one of the following statements is true concerning the current in wire A?
A)The current is one-fourth that in B.
B)The current is four times that in B.
C)The current is equal to the current in B.
D)The current is half as much as that in B.
E)It is twice as much as that in B.

Question

Quizplus · Accepted Answer

According to Ohm's law, current is directly proportional to voltage and inversely proportional to resistance. Since both wires are made of the same material and have the same diameter, their resistances are the same. However, wire A is twice as long as wire B, so it has twice the resistance. Therefore, to maintain the same potential difference across both wires, the current in wire A must be half that in wire B. So, the correct statement is that the current in wire A is half as much as that in B, which is option D.

Two Wires a and B Are Made of the Same