The UV- rays in atmosphere are checked by

Options

A. 1)`O_(3)`
B. 2)`O_(2)`
C. 3)`H_(2)`
D. 4)`Cl_(2)`

Answer

To solve the question "The UV-rays in atmosphere are checked by," we can follow these steps:

### Step 1: Identify the Options
The options given are:
1. O3 (Ozone)
2. O2 (Oxygen)
3. H2 (Hydrogen)
4. Cl2 (Chlorine)

### Step 2: Understand the Role of Each Compound
- **O3 (Ozone)**: Ozone is a molecule made up of three oxygen atoms. It is known to absorb a significant portion of the sun's harmful ultraviolet (UV) radiation.
- **O2 (Oxygen)**: Oxygen is a diatomic molecule and does not have a significant role in absorbing UV rays.
- **H2 (Hydrogen)**: Hydrogen is also a diatomic molecule and does not absorb UV radiation.
- **Cl2 (Chlorine)**: Chlorine is a diatomic molecule, but it does not primarily function to absorb UV rays in the atmosphere.

### Step 3: Determine the Correct Answer
From the analysis, it is clear that the compound that checks or absorbs UV rays in the atmosphere is **O3 (Ozone)**. The ozone layer, which is found in the stratosphere, plays a crucial role in protecting the Earth from harmful UV radiation emitted by the sun.

### Step 4: Conclude the Answer
Thus, the correct answer to the question is:
**O3 (Ozone)**