Among the following metals, which is the best electrical conductor under normal conditions?

Introduction / Context:
Electrical conductivity describes how easily electric charge can flow through a material. Metals are typically good conductors, but their conductivities differ. This question asks you to choose the best conductor of electricity among the common metals listed: aluminium, gold, silver and copper.

Given Data / Assumptions:

• We are dealing with pure metals at room temperature under normal conditions.
• No special alloys or superconductors are considered.
• We compare the intrinsic electrical conductivities of aluminium, gold, silver and copper.
• Practical factors such as cost and corrosion are not part of the question.

Concept / Approach:
The electrical conductivity of a metal depends on how freely its electrons can move. Among the common metals, silver has the highest electrical conductivity, followed by copper, gold and then aluminium. That is why, in ideal conditions, silver is considered the best conductor. In practice, copper is used more widely because it is cheaper and still very highly conductive, while aluminium is used where low weight is important. Gold is also a very good conductor and resists corrosion, so it is often used for contacts, but its conductivity is slightly lower than that of silver.

Step-by-Step Solution:
Step 1: Recall that conductivity is highest for silver among standard metals, based on measured values in reference tables. Step 2: Recognise that copper is a close second and widely used in wiring but not quite as conductive as silver in pure form. Step 3: Note that gold, while an excellent conductor and corrosion-resistant, is more expensive and slightly less conductive than silver and copper. Step 4: Aluminium is a good conductor but has lower conductivity than copper and silver; it is valued more for its low density and cost. Step 5: Therefore, among the given options, the best electrical conductor is silver.

Verification / Alternative check:
Standard tables show relative conductivities where silver is assigned the highest value (often normalised to 100 percent), copper slightly below, followed by gold and aluminium. For example, if silver is considered 100, copper is roughly 97, gold around 76 and aluminium around 61 in relative terms. This ranking is consistent across many physics and engineering references. Electrical components that demand the lowest resistance possible sometimes use silver plating on contacts to exploit this high conductivity.

Why Other Options Are Wrong:
Aluminium: Although a good and lightweight conductor, it is not as conductive as copper or silver; its main advantage is low weight and cost.

Gold: Gold is a very good conductor and does not corrode easily, but its conductivity is slightly lower than silver and copper.
Copper: Copper is highly conductive and widely used, but silver slightly surpasses it in electrical conductivity.

Common Pitfalls:
Because copper is so commonly used in wires and electrical cables, some students assume it must be the best conductor. Others are influenced by the high value of gold and assume its conductivity is the highest. Remember that practical use depends on both conductivity and factors like cost, weight and corrosion resistance, but the question here is purely about which metal has the highest electrical conductivity, and that distinction belongs to silver.

Final Answer:
Among the given metals, the best conductor of electricity is Silver.