This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

LED lamps have been advocated as the newest and best environmental lighting method. According to the Energy Saving Trust, LED lamps use only 10% power compared to a standard incandescent bulb, where compact fluorescent lamps use 20% and energy saving halogen lamps 70%. The lifetime is also much longer — up to 50,000 hours. A downside is still the initial cost, which is higher than that of compact fluorescent lamps.
How much more power does a standard incandescent bulb use compared to LED?

Southeast Asia has an area of approximately 4,000,000 km2 (1.6 million square miles). As of 2013, Around 625 million people lived in the region, more than a fifth of them (143 million) on the Indonesian island of Java, the most densely populated large island in the world. Indonesia is the most populous country with 255 million people as of 2015, and also the 4th most populous country in the world. The distribution of the religions and people is diverse in Southeast Asia and varies by country. Some 30 million overseas Chinese also live in Southeast Asia, most prominently in Christmas Island, Indonesia, Malaysia, the Philippines, Singapore, and Thailand, and also, as the Hoa, in Vietnam.
What is the approximate area of Southeast Asia?

The son of Murad II, Mehmed the Conqueror, reorganized the state and the military, and conquered Constantinople on 29 May 1453. Mehmed allowed the Orthodox Church to maintain its autonomy and land in exchange for accepting Ottoman authority. Because of bad relations between the states of western Europe and the later Byzantine Empire, the majority of the Orthodox population accepted Ottoman rule as preferable to Venetian rule. Albanian resistance was a major obstacle to Ottoman expansion on the Italian peninsula.

Who was the son of Murad II?