The ozone layer on the top of the stratosphere is crucial for human survival.Explain why?

Give reasons for the following: (i) Long distance radio broadcasts use short-wave bands. (ii) The small ozone layer on top of the stratosphere is crucial for human survival. (iii) Satellites are used for long distance TV transmission.

Assertion(A): The Ozone layer present at the top of stratosphere is very crucial for human survival. Reason (R): Ozone layer prevents IR radiation.

Why is the thin ozone layer on top of the stratosphere crucial for human survival? Identify to which a part of electromagnetic spectrum does this radiaton belong and write one important application of the radiation?

Answer the following: (a) Name the em waves which are used for the treatment of certain forms of cancer. Write their frequency range. (b) Thin ozone layer on top of stratosphere is crucial for human survival. Why? (c) An em wave exerts pressure on the surface on which it is incident. Justify.

Rakesh and Rajesh are 8th class students. They are fond of watching cricket match, particularly when it is played between Australia and India. They observed that most of the players, when they are in the field, apply a cream on their face. They did not know its reason. One day they asked this question to their teacher. The teacher thought it to be a good question and explained the reason for applying this cream to the whole class. Based on this paragraph, answer the following questions: (i) In your opinion, what explanation did the teacher offer to the students in the class? (ii) Why is small ozone layer on top of the stratosphere considered crucial for human survival? (iii) Write any two values displayed by Rakesh and Rajesh and their class teacher?

The ozone layer is earth's atmosphere is crucial for human survival because it