Match Fibre with Application.\[\begin{array}{|l|l|} \hline \textbf{LIST I} & \textbf{LIST II} \\ \textbf{Fibre} & \textbf{Application} \\ \hline \hline \text{A. Silk fibre} & \text{I. Fire retardant} \\ \hline \text{B. Wool fibre} & \text{II. Directional lustre} \\ \hline \text{C. Nomex fibre} & \text{III. Bulletproof} \\ \hline \text{D. Kevlar fibre} & \text{IV. Thermal insulation} \\ \hline \end{array}\]
Step 1: Analyze each term in List I and find its corresponding principle or instrument in List II.
- A. Tear strength: This measures the force required to propagate a tear in a fabric. A common method to test this is the Elmendorf tear tester, which works on a falling pendulum or impact principle.
- B. Water repellency: This measures a fabric's ability to resist wetting. The contact angle test, which measures the angle a water droplet makes with the fabric surface, is a direct way to quantify surface wettability and repellency. A higher contact angle means higher repellency.
- C. Seldom occurring faults: These are large, infrequent yarn faults (like slubs or long thick/thin places) that are not captured well by standard evenness testers. The Classimat is an instrument specifically designed to classify and count these seldom-occurring or "objectionable" faults.
- D. Spectrogram: A spectrogram is a graphical output from a yarn evenness tester. It plots the amplitude of mass variation against its wavelength, making it the primary tool for identifying periodic faults.
Step 2: Assemble the correct matches.
- A \(\rightarrow\) III
- B \(\rightarrow\) I
- C \(\rightarrow\) IV
- D \(\rightarrow\) II
Step 3: Find the corresponding option. The combination A-III, B-I, C-IV, D-II matches option (C). (Note: There is a typo in option D, it's identical to C).
The strength of fiber is usually measured in bundle form because there is better correlation between fiber bundle strength and \(\underline{\hspace{2cm}}\)