Question: Which of the following rays coming from the Sun plays an important role in maintaining the Earth's warmth?

Step 1 (Governing Principle): [0.5 Mark]

The Earth's warmth is primarily maintained by the Greenhouse Effect. Solar radiation consists of various electromagnetic waves. While visible light passes through the atmosphere to heat the Earth's surface, the surface re-radiates this energy as Infrared (IR) radiation. Greenhouse gases (like $CO_2$ and $CH_4$) in the atmosphere are highly effective at absorbing these infrared rays, trapping the heat and preventing it from escaping into space.

Step 2 (Analysis of Options): [0.25 Mark]

• (A) Infrared rays: These are thermal radiations associated with heat energy. They are absorbed by greenhouse gases, maintaining the Earth's temperature.
• (B) $\gamma$ rays: These are high-energy ionizing radiations absorbed by the upper atmosphere; they do not contribute to surface warmth.
• (C) UV rays: These are absorbed by the ozone layer and are primarily responsible for chemical reactions and skin damage, not thermal trapping.
• (D) Visible light rays: While these provide light, they are not the primary mechanism for "trapping" heat in the atmosphere.

Step 3 (Final Concluded Answer): [0.25 Mark]

The correct option is (A) Infrared rays.

💡 EL10 Concept Insight: Think of the Earth like a car parked in the sun; the sunlight goes through the windows, but the heat gets trapped inside because the glass doesn't let the heat waves back out easily. Infrared rays are those "heat waves" that get trapped by our atmosphere, keeping our planet cozy instead of freezing cold!