Question

Fine wire is drawn through diamonds, for making:
A. copper wire for motor coils
B. springs for watches
C. electrical conductors
D. fine embroidery

Answer 1

Hint: The rod or bars of metals are drawn into fine wires by using wire drawing technique. During the wire drawing process, the metal wires with very small diameter are produced from metal rods by using special tools.

Complete step by step answer:
The metal rod through a specific tool known as drawing die. The drawing die has a cone shaped hole to in it. The commonly used drawing dies are natural or artificial diamond dies, which are known for its precision and durability.
The diamond die has a structure which has two entrances with different diameters. Ione side has an entrance with a wide diameter to insert the metallic rod and another entrance with a smaller diameter to draw out fine wire.
The steel wires are drawn from steel rods by reducing the diameter of the rods. The volume of the steel remains the same during drawing, which increases the length of drawn wire. The drawn steel wires are used for making screws, springs, nails, wire stock for fences and so on.
In mechanical watches and alarm clocks, a hairspring or balance spring is used which is a spiral shaped fine wired spring.

So, the correct answer is Option B.

Additional information:
For drawing fine wires at high speed, most commonly used drawing die is of natural or synthetic diamond. The fine wires of diameter ranging from 2 micrometres to 1.5 millimetres can be drawn using diamond dies.

Note: Students might think that to make a fine wire, the metal rod should pass through the drawing die only once. To get a fine wire of desired thickness, a metal rod must pass through a series of drawing dies, each die has a smaller diameter than the previous one. The number of drawing dies may vary between 4 to 12.