With reference to 'fuel cells' in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements: 1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products. 2. Fuel cells can be used for powering buildings and not for small devices like laptop computers. 3. Fuel cells produce electricity in the form of Alternating Current (AC) Which of the statements given above is/are correct? Correct Answer 1 only The correct answer is 1 only. If pure hydrogen is used as a fuel, fuel cells emit only heat and water as byproducts. Hence statement 1 is correct. Fuel cells could power our cars, with hydrogen replacing petroleum fuels. Mistake Points Fuel cells can power almost any portable device or machine that uses batteries. Laptop computers, cellular phones, and hearing aids could be powered by portable fuel cells. Hence statement 2 is incorrect. Hydrogen-powered fuel cells are more energy-efficient than traditional combustion technologies. Fuel cells produce electricity in the form of direct current (DC). Hence statement 3 is incorrect.