Explain MHD generators, hydrogen fuel cell reactions and types, and compare fuel cells with batteries.

Here's the solution for Q2.a.i, Q2.a.ii, and Q2.b.i: Q2.a.i: Explain how an MHD generator produces electricity. An MHD (Magnetohydrodynamic) generator produces electricity by passing a hot, electrically conductive fluid (like plasma or ionized gas) at high speed through a strong magnetic field. This movement of the conductive fluid across the magnetic field induces an electric current and voltage, which can then be extracted by electrodes. This process directly converts thermal or kinetic energy into electrical energy based on Faraday's law of electromagnetic induction. Q2.a.ii: Write the overall reaction of a hydrogen fuel cell and list three types of fuel cells by electrolyte. The overall reaction of a hydrogen fuel cell is: 2H_2(g) + O_2(g) → 2H_2O(l) Three types of fuel cells by electrolyte are: • Proton Exchange Membrane Fuel Cell (PEMFC) • Solid Oxide Fuel Cell (SOFC) • Alkaline Fuel Cell (AFC) Q2.b.i: Compare a fuel cell with a battery (in terms of energy source, duration, emissions). • Energy Source: A fuel cell generates electricity from an external, continuously supplied fuel (e.g., hydrogen) and oxidant (e.g., oxygen from air). A battery stores its chemical reactants internally, providing a finite amount of stored energy. • Duration: A fuel cell can operate continuously as long as fuel and oxidant are supplied. A battery operates until its stored chemical energy is depleted, requiring recharging or replacement. • Emissions: A hydrogen fuel cell produces only water as a direct emission during operation, making it zero-emission at the point of use. A battery has no direct emissions during operation, but its overall environmental impact includes emissions from manufacturing, disposal, and the electricity source used for recharging. 3 done, 2 left today. You're making progress.