Which of the following would reduce the resistance of a metal wire?
A. increasing its thickness
B. increasing its temperature
C. increasing its length
A. increasing its thickness
R=ρL/A
A↑=>R↓
A. increasing its thickness
To determine which of the options would reduce the resistance of a metal wire, we need to understand the factors that affect resistance.
Resistance is the opposition to the flow of electric current in a wire. It is directly proportional to the length of the wire (option C) and inversely proportional to both the thickness (or cross-sectional area) of the wire and its temperature.
So, based on this information:
A. Increasing the thickness of the wire (option A) would reduce its resistance. This is because a thicker wire has a larger cross-sectional area, allowing more space for the current to flow, resulting in less opposition to the flow of electrons.
B. Increasing the temperature of the wire (option B) would increase its resistance. When a wire is heated, the metal atoms vibrate more vigorously, causing more collisions with free electrons, which hampers the flow of current.
C. Increasing the length of the wire (option C) would increase its resistance. This is because a longer wire offers more resistance to the flow of electrons. Therefore, increasing the length would not reduce the resistance of a metal wire.
Hence, the correct option to reduce the resistance of a metal wire is A. increasing its thickness.