हरित हाइड्रोजन (Green Hydrogen) के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए: I. हरित हाइड्रोजन का उत्पादन नवीकरणीय ऊर्जा स्रोतों द्वारा संचालित इलेक्ट्रोलिसिस द्वारा किया जाता है। II. इसे बिना किसी संशोधन के मौजूदा प्राकृतिक गैस पाइपलाइनों का उपयोग करके ले जाया जा सकता है। III. यह फ्यूल सेल इलेक्ट्रिक वाहनों (FCEVs) में कार्बन मुक्त ईंधन के रूप में कार्य करता है। उपरोक्त में से कितने कथन सही हैं?

Consider the following statements regarding perovskite solar cell technology: I. These solar cells are known for high power-conversion efficiency, but their long-term stability under sunlight remains a challenge. II. Compared with conventional silicon-based solar cells, perovskite cells are presently more expensive to manufacture even though their efficiency levels are approaching those of silicon cells. III. Disposal of such cells may raise environmental concerns because certain perovskite materials contain toxic heavy metals such as lead. Which of the statements given above are correct?

With reference to green hydrogen, consider the following statements: I. Green hydrogen is produced by the electrolysis of water powered by renewable energy sources. II. It can be blended and transported using existing natural gas pipelines up to certain limits without structural modifications. III. It serves as a carbon-free fuel in fuel cell electric vehicles (FCEVs). Which of the statements given above are correct?