Question

question 6 of 10
assuming that voltage remains constant, what happens to the current in a wire as its diameter decreases?
a. the current alternates between high and low values.
b. the current increases.
c. the current is not affected by a change in wire diameter.
d. the current decreases.

Explanation:

Ohm's law is \(I=\frac{V}{R}\), and the resistance formula is \(R =
ho\frac{l}{A}\) (\(
ho\) is resistivity, \(l\) is wire length, \(A\) is cross - sectional area). The cross - sectional area \(A=\pi(\frac{d}{2})^2\) (\(d\) is diameter). As \(d\) decreases, \(A\) decreases. Since \(R\) is inversely proportional to \(A\), \(R\) increases. Given \(V\) is constant, from \(I=\frac{V}{R}\), when \(R\) increases, \(I\) decreases.

Answer:

D. The current decreases.