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Published on: 27/09/2019
Some Natural Phenomena
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1.
During the natural disaster (Tsunami) in Japan, the nuclear reactors were damaged, due to which hazardous radiation affected the large areas.
(i) What was the reason for this damage?
(ii) How did it affect the people and environment?
(iii) Do you think that nuclear energy is good for nature?
2.
What are seismic waves? How can it be measured?
3.
What are lightning conductors? How is it used?
4.
Write Do's and Don'ts during a thunderstorm.
5.
Explain how do the buildings can be designed and constructed in seismic zones.
6.
If the materials used for constructing a building were good conductors, do you think lightning will strike the building? Will the lightning conductor be still required to be installed in the building?
7.
Is it possible to predict the occurrence of an earthquake?
8.
Explain the electric discharge occur in clouds.
9.
Mention three precautions that you will take to protect yourself if earthquake strikes when you are inside the house.
10.
If air and cloud are good conductors of electricity, do you think lightning could occur? Explain.
11.
You might have observed on a dry day that when you touch the screen of a television or computer monitor (with picture tube), you get a slight shock. Why does it happen?
12.
Identify the lightning conductor and the copper plate in figure.
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13.
Explain how does lightning conductor protect a building from getting struck by lightning.
14.
During the construction of a building, the lightning conductor was left hanging in the air by mistake. Would the lightning conductor be still effective? Explain.
15.
The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.
1.
(i) The uranium and other elements which radiate large amount of heat and energy and it is very harmful for living beings.
(ii) It affected the people on skin, eyes even on genes also and the particles got embedded in environment which continuous pollute it by emitting radiations.
(iii) When it is used in good of humans then only it is good because small amount of atom gives huge amount of energy.
2.
The tremor produces waves on the surface of the earth. These waves are called seismic waves. The waves are recorded by an instrument called the seismograph. This instrument is simply a vibrating rod or a pendulum, which starts vibrating when tremors occur. A pen is attached to the vibrating system that records the seismic waves on a paper. By studying these waves, scientists can construct a complete map of the earthquake.
3.
Lightning conductors are the devices used to protect buildings from the effect of lightning. It is a metallic rod, taller than the building, installed in the walls of the building during its construction. One end of the rod is kept out in the air and the other is buried deep in the ground. The rod provides easy route for the transfer of electric charge to the ground.
4.
Outside the house:
(i) Open vehicles, such as motorbikes, tractors, construction machinery, and open cars are not safe.
(ii) Open fields, tall trees, shelters in park, elevated place do not protect us from lightning strokes.
(iii) Carrying an umbrella is also not safe.
(iv) Stay away from poles or other metal objects.
Inside the house:
(i) During a thunderstorm contact with telephone cords, electrical wires and metal pipes should be avoided.
(ii) It is safe to use mobile phone.
(iii) Bathing should be avoided.
(iv) Electrical appliances like computers, TVs etc. should be unplugged. Electrical lights can remain on.
5.
Since, in seismic zones, all the houses and buildings should be designed and constructed in such a way, so that they can withstand major earthquake tremors.
6.
Lightning will not strike the building because all the lightning falling on the building will reside on the surface of the building. Now, there is no need of installing any lightning conductor because all the work of lightning conductor is done by the conducting material itself.
7.
No, scientists have tried lots of different ways of predicting earthquake but none have been successful so far. They have a pretty good idea of where an earthquake is most likely to hit but they still cannot tell exactly when it will happen.
8.
Since, during thundering, negative charges get accumulated near the clouds and positive charges accumulate near the ground. So, when these charges meet, then electric discharge takes place between ground and clouds. So, a large amount of energy is released in the form of thunder and lightning.
9.
Three precautions during earthquake inside the house are as follows:
(i) Instead of running away, we should get under a desk, table or bench or sit against a nearby interior wall.
(ii) Pick a safe place where things will not fall on you, away from windows, bookcases or tall heavy furniture.
(iii) Wait at your safe place until the shaking stops.
10.
No, there will not be lightning at all because all the charges collected at the clouds will continuously transfer through air and there will be no lightning.
11.
It happens because the television screen or computer monitor are charged and have static charges and when we touch them with our hands which are uncharged, the charges attract our hands and transfer through our hands and we get a small shock.
12.
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13.
Lightning conductor is connected with a wire which is finally connected to a copper plate and copper plate is grounded. So, when lightning occurs, all the charge is transferred through this conductor and reach to the ground and building gets no harm.
14.
Lightning conductor will not work if left hanging in the air because, in order to work, it must be installed properly and grounded using any metal (copper) plate.
15.
Carrying an umbrella is not advisable during thunderstorm. As the rod of umbrella and its supporting wires are made up of metals. Thus, during thunderstorm, the conducting objects should be avoided.
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