Question

How many long wires can be drawn from a gram of gold?
(A) 3 centimeter
(B) 3 meter
(C) 3 kilometer
(D) 300 meter

Answer 1

Hint: Think about the ductility property of gold. 1 ounce of gold can be stretched up to 50 miles long wire. One ounce of gold is equal to 28.35grams of gold. In the question, we need to find out the length of wire that is drawn from one gram of gold. Just cross-multiply the values and find the answer.

Complete step by step solution:
- Gold is an inert metal which has high ductility property and therefore, it is used in making ornaments.
- One ounce of gold can be drawn into a wire having a length of up to 50 miles.
- One ounce of gold is equal to 28.35grams.
\[\begin{align}
& 28.35g\equiv 50miles \\
& 1g=\dfrac{50}{28.35}=1.764miles \\
\end{align}\]
- Now, we have calculated that one gram gold can be drawn into 1.764miles long wire.
- In the question, options are given in terms of meter.
- We know that, 1mile = 1.61km
- Therefore, $1.764$ $miles =$ $1.764\times 1.61$ $=2.84$ $kilometres$.
- 2.84 kilometres is very close to 3 kilometres so it can be approximated as 3kilometres.
- Therefore, one gram gold can be drawn into 3km long wire.

Therefore, the answer is option (C).

Note: Remember 1g gold can be drawn into a wire which is 3km long and about 5microns in thickness. Gold is one of the most ductile metals in the whole periodic table. Also, remember 1ounce gold is equal to 28.35grams of gold which can be drawn into a 50miles long wire having 5microns thickness.