निम्नलिखित पदार्थों को उनके पहली बार प्रयोगशाला में संश्लेषण के कालक्रमानुसार व्यवस्थित कीजियेः 1. ब्लैक गोल्ड 2. फुलेरीन 3. ग्रैफीन 4. केवलार नीचे दिये गये कूट में से सही उत्तर चुनिए / Arrange the following substances in chronological order of their first synthesis in lab: 1. Black gold, 2. Fullerene, 3. Graphene, 4. Kevlar. Select correct answer from the codes given below:
Explanation:
The approximate first synthesis/discovery dates are: Kevlar (1965), Fullerene (1985), Graphene (2004). 'Black Gold' is an ambiguous term in this context; if it refers to carbon nanotubes, they were observed in the early 1990s (e.g., 1991). The chronological order would be Kevlar (4), Fullerene (2), Carbon Nanotubes (1), Graphene (3), i.e., 4, 2, 1, 3. Since this exact order is not an option, and assuming 'Black Gold' might refer to a very recent material or there's a specific context for this question, option (b) places Black Gold last (after Graphene). Given the options, and the ambiguity of 'Black Gold', option (b) is chosen as the most plausible intended answer, assuming 'Black Gold' is a very recent material or the question is flawed.