medium importancemedium difficulty5 min

Ozone Layer

The ozone layer is a region in the stratosphere that contains a high amount of ozone gas and absorbs harmful ultraviolet rays from the Sun.

In one line: Ozone is Earth's UV shield.

Practice This Concept

Understand it

The ozone layer acts like a protective shield for life on Earth. It reduces the amount of UV radiation reaching the surface, which helps protect living organisms from skin damage, eye problems, and harm to plants. Ozone depletion weakens this protection.

Example

When ozone is reduced by pollutants like CFCs, more ultraviolet rays can reach Earth and increase health risks.

Rule to remember

Ozone in the stratosphere absorbs UV radiation and helps protect life on Earth.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

1If the ozone layer becomes thinner, more UV rays reach humans and plants.
2This can increase skin damage and disturb normal growth in living beings.

Method you can reuse

1Identify the layer as part of the stratosphere.
2State what it absorbs.
3Mention the benefit to life.
4Add one effect of depletion.

Sketch it in your answer

Show the atmosphere with the stratosphere labelled and arrows of UV rays being blocked by the ozone layer.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

What is the main function of the ozone layer for life on Earth?

Think first, then show answer

The main function of the ozone layer is to absorb harmful ultraviolet rays from the Sun. This protects living organisms from excess UV damage.

Common wrong answer

A common wrong answer is to say the ozone layer provides oxygen for breathing.

Why it loses marks: Its main role is UV protection.

Don't mix this up

Students often think the ozone layer produces oxygen for breathing. Its main role is protection from ultraviolet radiation, not oxygen supply.

Exam tip

In exam answers, mention stratosphere, ultraviolet rays, and protection together for a complete response.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

State the function of the ozone layer, explain ozone depletion, or describe why it is important for life.

1
Enough for 1 mark
The ozone layer is a region in the stratosphere that contains a high amount of ozone gas and absorbs harmful ultraviolet rays from the Sun.
2
Add for 2 marks
Example: When ozone is reduced by pollutants like CFCs, more ultraviolet rays can reach Earth and increase health risks.
3
Add for 3 marks
The ozone layer acts like a protective shield for life on Earth.

MCQ Quiz

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