Match the items in Column A with the items in Column B. Column A Column B 1. Seismograph a. An electric spark on a huge scale in the sky 2. Richter scale b. Transfer of electric charge from a charged object to the earth 3. Seismic zones c. Passage of electric current in the air due to movement of charges 4. Earthquake d. Expresses the intensity of an earthquake 5. Weak zones e. Detects the presence of electric charge on an object 6. Seismic waves f. Areas prone to earthquakes 7. Earthing g. Sudden shaking of the earth 8. Electroscope h. Boundaries of the earth's plates 9. Discharge I. Waves generated by an earthquake 10. Lightning j. Records seismic waves

Seismograph Records seismic waves A seismograph is an instrument which measures and records the magnitude of an earthquake in terms of the shock waves it produces. A seismograph is also known as a seismometer. Richter scale Expresses the intensity of an earthquake Charles F. Richter developed the Richter scale in 1935 . The magnitude (or intensity) of an earthquake is expressed on the Richter Scale. Seismic zones Areas prone to earthquakes Earthquakes are caused by the movements of plates of the earth, the boundaries of the plates are the weak zones where earthquakes are most likely to occur. Earthquake Sudden shaking of the earth Earthquakes are caused by the movements of earth's plates, the boundaries of the plates are the weak zones where earthquakes are most likely to occur. Weak zones Boundaries of earths plate Earthquakes are caused by the movements of earth's plates, the boundaries of the plates are the weak zones where earthquakes are most likely to occur. Seismic waves Waves generated by an earthquake Seismic waves are the waves generated during an earthquake. The intensity of seismic waves measured by seismograph. Earthing Transfer of electric charge from a charged object to the earth The main objective of the Earthing system is to provide an alternative path for dangerous currents to flow so that accidents due to electric shock and damage to the equipment can be avoided. Electroscope Detects the presence of electric charges on an object Electroscope detects the presence of electric charge on an object. The electroscope works based on like charges repel each other. Discharge Passage of electric current in the air due to movement of charges The crackling sound heard when one takes off woollen clothes are tiny sparks. These charges move in streams between the sweater and our body, i.e. electric discharge takes place. Lightning An electric spark on a huge scale in the sky Lightning strikes are more frequent in hilly areas than in the planes. In hilly areas, clouds are comparatively closer to the ground than in the plains. Column A Column B 1. Seismograph j. Records seismic waves 2. Richter scale d. Expresses the intensity of an earthquake 3. Seismic zones f. Areas prone to earthquakes 4. Earthquake g. Sudden shaking of the earth 5. Weak zones h. Boundaries of the earth's plates 6. Seismic waves I. Waves generated by an earthquake 7. Earthing b. Transfer of electric charge from a charged object to the earth 8. Electroscope e. Detects the presence of electric charge on an object 9. Discharge c. Passage of electric current in the air due to movement of charges 10. Lightning a. An electric spark on a huge scale in the sky

Earthing is the process of connecting the exposed metal parts of an electrical circuit to the ground. This is done to avoid accidental shock. If the earth wire is properly connected to the metallic body, it protects us from an electric shock. It is the flow of current directly to the earth through a low resistance path.

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Study Mate Science Class 8>Chapter 15 - Some Natural Phenomena>NUT Cracker>Q IV

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Charging an object by touching it to a charged object is known as:

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Important Questions on Some Natural Phenomena

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Study Mate Science Class 8>Chapter 15 - Some Natural Phenomena>NUT Cracker>Q IV

Tsunami is a Japanese word which means:

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Study Mate Science Class 8>Chapter 15 - Some Natural Phenomena>NUT Cracker>Q IV

A gold-leaf electroscope can

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Study Mate Science Class 8>Chapter 15 - Some Natural Phenomena>NUT Cracker>Q V

Match the items in Column A with the items in Column B.

Column A	Column B
1. Seismograph	a. An electric spark on a huge scale in the sky
2. Richter scale	b. Transfer of electric charge from a charged object to the earth
3. Seismic zones	c. Passage of electric current in the air due to movement of charges
4. Earthquake	d. Expresses the intensity of an earthquake
5. Weak zones	e. Detects the presence of electric charge on an object
6. Seismic waves	f. Areas prone to earthquakes
7. Earthing	g. Sudden shaking of the earth
8. Electroscope	h. Boundaries of the earth's plates
9. Discharge	I. Waves generated by an earthquake
10. Lightning	j. Records seismic waves