A solar water heater cannot be used to get hot water on
(a) a sunny day (b) a cloudy day
(c) a hot day (d) a windy day
(b) A solar water heater uses solar energy to heat water. It requires bright and intense sunlight to function properly. On a cloudy day, the sunlight reflects back in the sky from the clouds and is unable to reach the ground. Therefore, solar energy is not available for the solar heater to work properly. Hence, solar water heater does not function on a cloudy day.