Ocean thermal energy is due to [NCERT Exemplar Problems] (a) energy stored by waves in the ocean (b) temperature difference at different levels in the ocean (c) pressure difference at different levels in the ocean (d) tides arising out in the ocean

Answer: b Explanation: (b) Energy of warm surface water used to vaporise the low boiling point liquid ammonia. This vapours at high pressure is used to strin the turbines to generate electricity. Deep ocean cold water again condenses the used vapour into liquid.