Q: 45 (IAS/2015)
question_subject:
Science
question_exam:
IAS
stats:
0,140,94,140,12,51,31
keywords:
{'fuel cells': [0, 0, 0, 1], 'fuel cell': [0, 0, 0, 3], 'electricity': [0, 0, 1, 3], 'pure hydrogen': [0, 0, 0, 1], 'hydrogen': [0, 0, 1, 3], 'fuel': [1, 0, 5, 14], 'ac': [0, 1, 0, 2], 'current': [0, 0, 0, 3], 'oxygen': [3, 0, 1, 0], 'rich fuel': [0, 0, 0, 1]}
The correct statements are:
1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products. (Correct)
2. Fuel cells can be used for powering buildings and not for small devices like laptop computers. (Incorrect - Fuel cells can be used for both large-scale applications, such as powering buildings, as well as small devices like laptop computers.)
3. Fuel cells produce electricity in the form of Alternating Current (AC). (Incorrect - Fuel cells produce electricity in the form of Direct Current (DC), not Alternating Current (AC).)
Therefore, the correct answer is:
1 only.