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Question

Which is the lightest among the following commonly used workshop materials?

This question was previously asked in
RRB ALP 2025 CBT 2 Wiremen Question Paper (28-Jul-2026) (Shift 2)
The correct answer is

Aluminum rod

For rods of the same size, weight depends on the material's density — mass per unit volume — so the lightest rod is simply the one made of the least dense metal.

The governing comparison is therefore between the densities of the four listed workshop materials.

Aluminium has a density of about 2.7 g/cm3, which is markedly lower than the others.

Steel and iron both sit around 7.8 g/cm3, roughly three times aluminium's density, so equal-sized steel and iron rods weigh about three times as much.

Copper is denser still at about 8.9 g/cm3, making a copper rod the heaviest of the group for the same size.

This large density gap is why aluminium is widely chosen where reducing weight matters, such as pistons and alloy wheels, without needing the strength of steel.

Since aluminium has by far the lowest density, an aluminium rod is the lightest of the four.

Hence, the answer is Aluminum rod.

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Similar Questions

  1. In Stress & Strain diagram, stress is always represented on the ______.

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  3. Which is the purest form of iron?
  4. Which component is made with cast iron?
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  7. Which one of the following is NOT a synthetic material of bearing?
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Important Questions from Metals and Properties

  1. In general, resistivity of an alloy ______ its constituent metals.

  2. In Stress & Strain diagram, stress is always represented on the ______.

  3. Which of the following statements about the resistivity of metals is INCORRECT?

  4. Aluminium in its pure form is not used for engineering work because

  5. The ability of a metal to withstand shock and impact

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