Question

A Solar water heater cannot be used to get hot water on :

• A. cloudy day
• B. sunny day
• C. a hot day
• D. a windy day

Hint:

"Solar" means it uses the sun. No sun, no (or very little) hot water.
{Cloudy day} = No/little sun \(\rightarrow\) Heater doesn't work well.
Sunny day = Lots of sun \(\rightarrow\) Heater works well.

Answer 1

The Correct Option is A

Concept: Solar water heaters rely on solar radiation (sunlight) as their energy source to heat water. Step 1: How solar water heaters work They have collectors (often black panels) that absorb sunlight. This absorbed energy heats water that circulates through the collectors. The effectiveness directly depends on the amount of sunlight received. Step 2: Analyzing the conditions
(1) Cloudy day: Clouds block most of the direct sunlight. Without significant sunlight reaching the collectors, the solar water heater cannot absorb enough energy to heat the water effectively. So, it "cannot be used" or will perform very poorly.
(2) Sunny day: This is the ideal condition. Ample sunlight allows the heater to work efficiently.
(3) A hot day: Hot ambient temperature can even improve efficiency by reducing heat loss from the collectors. If it's hot and sunny, it works well. If it's hot but cloudy, the lack of sun is still the limiting factor.
(4) A windy day: Wind can increase heat loss from the collectors, potentially reducing efficiency (water might not get as hot or take longer). However, if it's sunny, the heater will still work, just less optimally than on a calm sunny day. It can still be used. Step 3: Identifying the most prohibitive condition The primary requirement for a solar water heater is sunlight. A cloudy day deprives it of this essential energy source, making it largely ineffective.