i. The plates of earth's crust are in continual motion.
ii. Like charges repel and unlike charges attract each other.
iii. In an electroscope, the aluminium leaves diverge because like charges repel.
iv. Earthing is provided in buildings to protect us from electrical shocks due to any leakage of electrical current.
v. Lightning is also an electric spark, but on a huge scale.
vi. The outermost layer of the earth is not in one piece. It is fragmented. Each fragment is called a plate.
i. Like charges attract each other. F
ii. A charged glass rod attract a charged plastic straw. T
iii. Lightning conductor cannot protect a building from lightning. F
iv. Earthquakes can be predicted in advance. F
v. An earthquake of magnitude 6 has thousand times more destructive energy than an earthquake of magnitude 4. T
vi. Earthquakes tend to occur at the boundaries of earth’s plates. T
Ans. Gujarat, Kashmir, Rajasthan
Ans. A glass rod can be charged by rubbing it with silk cloth.
Ans. There are two kinds of charges — positive charge and negative charge.
Ans. A ballpoint pen refill can be charged by rubbing it against the woolen cloth.
Ans. Earth can be divided into three main layers: the core, the mantle and the crust.
Ans. When two like charges are brought together then they will repel each other.
Ans. The Richter scale is used to measure the magnitude (or intensity) of an earthquake.
Ans. Focus of an earthquake is located below the epicenter of an earthquake.
Ans. The plastic comb acquires negative charge when it is rubbed with dry hair.
Ans. An inflated balloon can be charged by rubbing it against the woolen cloth.
Ans. The place inside the earth’s crust where the earthquake begins is called focus of an earthquake.
Ans. Seismograph is the instrument which is used to measure and record an earthquake.
Ans. The point on the earth’s surface directly above the focus is called epicentre of an earthquake.
Ans. When balloon is rubbed with a woolen cloth, it acquires negative electric charge.
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