Choose the correct order of electrical resistivity of the metals mercury (Hg), nickel (Ni), tungsten (W), and silver (Ag), from highest resistivity to lowest resistivity.

Introduction / Context:
Electrical resistivity is a measure of how strongly a material opposes the flow of electric current. Metals generally have low resistivity, but there are still differences among them, which affect where they are used in electrical circuits and devices. This question asks you to arrange four metals, mercury (Hg), nickel (Ni), tungsten (W), and silver (Ag), in order of resistivity from highest to lowest. Understanding typical resistivity values helps you quickly determine which metals are better conductors and which are poorer conductors.

Given Data / Assumptions:
– The metals to compare are mercury, nickel, tungsten, and silver.
– The order requested is from highest resistivity (poorest conductor) to lowest resistivity (best conductor).
– Options are four different sequences using the symbols Ag, W, Ni, and Hg with greater than signs between them.
– We assume standard resistivity values at room temperature as given in physics reference tables.

Concept / Approach:
Silver is well known as one of the best electrical conductors and therefore has very low resistivity. Tungsten and nickel have higher resistivity than silver but still conduct reasonably well and are used where mechanical strength or specific properties are needed. Mercury, a liquid metal, has significantly higher resistivity than most solid metals and is a comparatively poor conductor. If we rank these metals by resistivity from highest to lowest, mercury comes first, followed by nickel, then tungsten, and finally silver. When written using the greater than sign to indicate greater resistivity, this order becomes Hg > Ni > W > Ag. The other sequences either place silver at the wrong end or misorder the intermediate metals, which does not match standard resistivity data.

Step-by-Step Solution:
Step 1: Recall that silver (Ag) has one of the lowest electrical resistivities among metals and is therefore the best conductor in this group. Step 2: Remember that mercury (Hg), despite being a metal, has relatively high resistivity and is a poorer conductor compared to most solid metals listed. Step 3: Recognise that nickel (Ni) and tungsten (W) have intermediate resistivity values, higher than silver but lower than mercury. Step 4: Arrange the metals from highest to lowest resistivity as Hg (highest) > Ni > W > Ag (lowest). Step 5: Match this arrangement to the given options and identify Hg > Ni > W > Ag as the correct choice.

Verification / Alternative check:
Physics handbooks or data tables list typical electrical resistivity values at room temperature. Silver has a resistivity around 1.6 × 10^-8 ohm metre, which is among the lowest of all metals. Tungsten and nickel have higher values, while mercury has a resistivity significantly larger than those of solid metals. Comparing these numbers confirms the relative order: mercury has the highest resistivity, followed by nickel and tungsten, and silver has the lowest. Translating this into a descending order using greater than signs yields Hg > Ni > W > Ag, validating the selected option.

Why Other Options Are Wrong:
Ag > W > Ni > Hg: This sequence incorrectly places silver at the highest resistivity end, contradicting the fact that silver is an excellent conductor with very low resistivity.
Ag > Ni > Hg > W: Again, this option wrongly suggests silver has the highest resistivity; it also misorders the remaining metals compared with standard data.
Ag > W > Hg > Ni: This arrangement both misplaces silver at the high resistivity end and does not reflect the correct relative positions of mercury, tungsten, and nickel based on their resistivity values.

Common Pitfalls:
Students may remember that silver is an excellent conductor but get confused by the direction of the greater than symbol in the options. They might read Ag > W > Ni > Hg as meaning silver has the lowest resistivity when actually the symbol indicates greater value on the left. Another mistake is to assume that all solid metals have lower resistivity than a liquid metal like mercury without recalling specific numerical values. To avoid these errors, always check what the question is asking (highest to lowest or lowest to highest) and remind yourself that a greater than sign means more resistive when you are ordering resistivity values. Keeping a mental picture that silver sits at the low resistivity end of almost any list will also guide you toward the correct sequence.

Final Answer:
The correct order of electrical resistivity from highest to lowest for the given metals is Hg > Ni > W > Ag.