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: Identify the principle or instrument from List II that corresponds to each term in List I.
- A. Tear strength: Tear strength quantifies the force needed to continue a tear in fabric. The Elmendorf tear tester, based on the impact principle (falling pendulum), is commonly used.
- B. Water repellency: This measures a fabric's resistance to wetting. The contact angle test assesses repellency by measuring the angle between a water droplet and the fabric surface; a larger angle indicates greater repellency.
- C. Seldom occurring faults: These are infrequent yarn flaws (e.g., slubs, thick/thin places) that standard testers often miss. The Classimat instrument is designed to classify and count these "objectionable" faults.
- D. Spectrogram: A spectrogram, a graphical output from a yarn evenness tester, plots mass variation amplitude against wavelength, making it ideal for identifying periodic faults.
Step 2: Match the terms and principles/instruments.
- A \(\rightarrow\) III- B \(\rightarrow\) I- C \(\rightarrow\) IV- D \(\rightarrow\) II
Step 3: Select the correct option. The combination A-III, B-I, C-IV, D-II corresponds to option (C). (Note: Option D contains a typo; it is identical to C).
The strength of fiber is usually measured in bundle form because there is better correlation between fiber bundle strength and \(\underline{\hspace{2cm}}\)