In metals and heat transfer, which of the following metals has the highest thermal conductivity and is therefore most efficient at conducting heat?

Introduction / Context:
Thermal conductivity is a property that measures how well a material can conduct heat. Metals are generally good conductors of both heat and electricity, but some metals are better conductors than others. Understanding which metals have the highest thermal conductivity is important for selecting materials in applications such as cookware, heat exchangers, and electronic devices. This question asks which of the listed metals has the maximum thermal conductivity.

Given Data / Assumptions:

• The metals listed are iron, aluminium, silver, and copper.
• All of them are known to be decent conductors of heat.
• We compare their thermal conductivities under normal conditions.
• We assume pure metals, not alloys or coated materials.

Concept / Approach:
Among common metals, silver has the highest thermal conductivity, followed closely by copper and then aluminium. Iron has significantly lower thermal conductivity than these three, which is one reason why it is not the best material for rapid heat transfer applications. Despite silver having the highest thermal conductivity, it is rarely used for large scale heat conduction because of its high cost. Copper is often chosen as a compromise between performance and price. However, in terms of pure thermal conductivity values, silver is the top conductor among the metals listed in the question.

Step-by-Step Solution:
Step 1: Recall that all four listed metals conduct heat, but not equally well. Step 2: Recognise that iron is less conductive than aluminium, copper, and silver, and is seldom used where maximum heat transfer is required. Step 3: Remember that aluminium has good thermal conductivity and is often used in cookware and heat sinks due to its low density and cost. Step 4: Note that copper has better thermal conductivity than aluminium and is widely used in heat exchangers and high quality cookware. Step 5: Understand that silver has even higher thermal conductivity than copper and is known as the best conductor of heat among common pure metals. Step 6: Conclude that silver is the metal with the maximum thermal conductivity among the options given.

Verification / Alternative check:
Tables of physical properties of metals show that the thermal conductivity of silver is higher than that of copper, aluminium, and iron. For example, at room temperature, silver has a thermal conductivity of roughly 400 watts per metre per kelvin, copper slightly less, aluminium lower still, and iron considerably lower. These numerical comparisons from reliable data sources confirm that silver leads in thermal conductivity among the metals listed. Textbooks also mention silver as the best conductor of both heat and electricity among common metals, reinforcing this conclusion.

Why Other Options Are Wrong:
Iron has relatively modest thermal conductivity compared with copper, aluminium, and silver and is not the maximum conductor among these choices. Aluminium conducts heat well but is clearly surpassed by copper and silver. Copper is an excellent conductor and is often called a very good heat conductor, but data show that silver still slightly exceeds copper in conductivity. Therefore, while copper is a strong candidate, it is not the maximum. Only silver satisfies the requirement of having the highest thermal conductivity among the listed metals.

Common Pitfalls:
A common mistake is to choose copper because it is famous for electrical wiring and heat exchangers, and many students are more familiar with copper than silver in practical applications. Another pitfall is to assume that the most widely used metal in industry for heat conduction must have the highest conductivity, ignoring cost and availability considerations. To avoid such errors, remember that silver is the best pure metallic conductor of both heat and electricity, but copper is used more widely because it is cheaper. Separating physical property rankings from practical usage helps in answering such questions correctly.

Final Answer:
The metal with the maximum thermal conductivity among the listed options is silver, a noble metal with very high conductivity.