in a closed circuit, when a short power cord is replaced with a long power cord, which of the following…

Explanation:

Step1: Recall resistance formula

The resistance formula is $R = \rho\frac{l}{A}$, where $\rho$ is the resistivity of the material, $l$ is the length of the conductor, and $A$ is the cross - sectional area.

Step2: Analyze the effect of length change

When a short power cord is replaced with a long power cord, the length $l$ of the conductor increases while the resistivity $\rho$ and cross - sectional area $A$ (assuming the same type of cord material and thickness) remain constant. According to the formula $R = \rho\frac{l}{A}$, as $l$ increases, the resistance $R$ increases.

Step3: Analyze other options

Voltage is provided by the power source and is not affected by the length of the cord in a simple circuit context. Insulation is a property of the material around the conductor and not directly related to the length change of the conducting part. Conductivity is the reciprocal of resistivity and is a material property that does not change with the length of the cord.

Answer:

C. resistance