When the length of a wire is reduced, what effect does it have on resistance?

• A. The resistance decreases
• B. The resistance doubles
• C. The resistance remains constant
• D. The resistance quadruples

Answer: (A)

When the length of a wire is reduced, the resistance decreases. This is due to the fundamental relationship between resistance, length, and material properties defined by Ohm's Law and the resistivity equation. Resistance (R) is directly proportional to the length (L) of the wire, expressed as R = ρ(L/A), where ρ is the resistivity of the material and A is the cross-sectional area.

As the length of the wire decreases, the path that the electrons must travel is shorter, which leads to fewer collisions with atoms in the wire's material. This means that the overall resistance faced by the flow of electric current is lowered. Thus, if the length is reduced, the resistance correspondingly decreases, affirming that the correct answer reflects this fundamental principle of electrical resistance.