Question

4.1.2 quiz: electricity
question 8 of 10
what happens to a circuits resistance (r), voltage (v), and current (i) when you decrease the length of the wire in the circuit?
a. r increases.
v is constant.
i decreases.
b. r increases.
v decreases.
i decreases.
c. r is constant.
v increases.
i increases.
d. r decreases.
v is constant.
i increases.

Explanation:

• Resistance formula: \(R =

ho\frac{l}{A}\) (where \(
ho\) is resistivity, \(l\) is length, \(A\) is cross - sectional area). When \(l\) (length of wire) decreases, \(R\) (resistance) decreases.

• Voltage (\(V\)) of the power source in a simple circuit (assuming ideal power source) is constant.
• According to Ohm's law \(I=\frac{V}{R}\). Since \(V\) is constant and \(R\) decreases, \(I\) (current) increases.

Answer:

D. \(R\) decreases. \(V\) is constant. \(I\) increases.