Page 202 - Science Class 08

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i A cloud may build up a positive charge or negative charge or different charges.
i Sometimes, a huge amount of charge flings towards the earth to get neutralised in the form
of lightning.
i Lightning, sometimes, becomes destructive.
i We can take safety measures to avoid the effect of lightning.

i A lightning conductor attract the charges of lightning and allow it to pass to the earth.
i Earthquakes are the most devastating because we cannot predict them earlier.
i An earthquake is a sudden movement of the ground produced by abrupt displacement of
rock masses, usually within the upper 15 to 20 km of the earth's crust.
i Earthquake can also cause floods, landslides and tsunamis.
i Most earthquakes result from the movement of one rock mass to another in response to
tectonic forces.
i There are two major scale in which earthquakes are measured. These are the Mercalli Scale
and the Ritcher Scale.
i The seismic zones in India are Kashmir, Western and Central Himalayas, the whole of
North-East, Rann of Kutch, Rajsthan and the Indo-Gangetic plain.

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A. Tick (3) the correct op on.
1. Which of the following is not a good idea to protect ourselves from the earthquake?
(a) Do not stand near a tree. (b) Do not carry umbrella.
(c) Do not lie on the ground. (d) Rush to an open field.

2. Which of the following is not caused by an earthquake?
(a) Flood (b) Tsunami
(c) Landslide (d) Cyclone
3. Which of the following terms is not related to earthquake?
(a) Focus (b) Epicentre

(c) Magnitude (d) Vent
4. Which of the following regions does not come in the seismic zone of India?
(a) Rajasthan (b) Rann of Kutch

(c) North East (d) Madhya Pradesh
B. Fill in the blanks.
1. Some mes, a huge amount of charge flings towards the earth to get ________________ in
the form of lightning.
2. The sound of thunder is an ___________________ to rush to a safer place.
3. __________________ is a device used to protect buildings from the effect of lightning.
4. Most earthquakes result from the movement of one rock mass to another in response to
_________________.

202 Science-8