GCERT Class 9 Social Science Chapter 20 Solution

1. What should be done during flood ?
Ans. During the time of flood we should follow the below steps:
1) Collect our precious and personal requirements and take refuge at a safer place.
2) Put water, dry breakfast, candles, lanterns, matchbox, in a plastic box so that they do not get wet, and they should be kept with us.
3) Do not keep the children hungry.
4) After the flood recedes, we should drink only boiled water.
5) Be aware of snakes. They may come to dry places. Keep a bamboo sticks to drive them away.

2. Give the brief account of tsunami.
Ans. The destructive and powerful sea waves are called Tsunami. Tsunami means ‘Destructing waves’ in Japanese language. There are generated at bottom on sea due to a) Earthquake having a rating of 7 or more on Richter scale, b) Volcanic eruption within sea or c) large scale landslide on ocean floor. The tsunami on most cases occur due to earthquake on ocean flood, so these are also known as ‘oceanic earthquake waves’. These waves travels fast in a circular pattern from the place of their origin. In deep sea they are not visible due to short wave heights. As they approach coasts and shallow sea their velocity reduce and height increases. They surge ahead in form of wall near a sea coast and cause devastation.

3. What should not be done at the time of gas leakage ?
Ans. During gal leakage following thing should be avoided:
1) Gathering of people who are not associated with rescue work.
2) Not entering the gas leakage area till it is declared totally safe by the authorities.
3) To not join rescue operation without proper training and necessary equipment.

4. Discuss the remedies to remain safe from viral diseases.
Ans. During viral epidemic people should follow following remedies to remains safe:
1) Be vigilant about the infection.
2) Get acquainted with the reasons, results and safety about diseases through propaganda and transmissions.
3) Take anti-disease vaccines.
4) Arrange for a special separate ward for patients’ treatment.
5) Take steps as per the guidelines and instructions issued by world Heath Organization (WHO), an international institution to curb viral diseases.

5. What is called a “Traffic Jam” ? What are its effects ?
Ans. Traffic Jam means complete stop or slow motion of vehicles which are close to one another on road. Traffic jams usually occur in large cities. It has following effects:
1) Develop mental stress among vehicle drivers, travellers and pedestrians.
2) The smoke from vehicle causes air pollution and sound causes noise pollution.
3) It affects the public hygiene and the growth of vegetation.
4) Causes loss of time and fuel.