B PLUSTOPPER

  Exercises I. Fill in the blanks below Most earthquakes occur on account of the strain in the  earth’s crust. P (primary or push waves)  are the first earthquake waves to be recorded on a seismograph of an earthquake. The last of the earthquake waves to arrive on the surface of the earth are  L (surface or long)  waves. The giant sea waves caused by earthquakes in the oceans are called  Tsunamis. About 70 per cent of the earthquakes occur in the  Circum- Pacific-Mountain  Belt. II. Short Answer Questions Question 1. What is called an earthquake ? Answer: An earthquake is defined as a tremor below the surface of the earth which causes shaking of the earth. Question 2. State two natural causes of an earthquake. Answer: Natural causes are the movement of tectonic plates and volcanic activities. Question 3. Name one man-made cause of an earthquake. Answer: Construction of large scale dams, thrust of rivers along fault lines, dumping of chemical wastes also cause earthquakes due to imbalan

  Argumentative Essay ICSE 2016 “The use of Mobile phones must be allowed in schools.” Express your views either for or against the statement. (ICSE 2016) Introduction: Mobile phones should not be allowed in schools for it adversely affects the students’ education, social development and health. Mobile phones distract students and teachers during class. Use of mobile phones in school vitiates the academic environment. Mobile phones are an important device for cheating during examinations. Their excessive use has also been found to be hazardous for health. Mobile phone stunts the social development of the student. Arguably there can be emergencies. An emergency parents can always access the school administration or teachers on their phones. Conclusion: Mobile phones must not be allowed in schools for it hampers learning and vitiates the academic environment. In recent times mobile phones, especially smart phones have become a valuable tool for communication, education and entertainment.

  Access Answers of Selina publication ICSE Class 9 Chemistry Chapter 3 Water Exercise :3 1. Water exists in all the three states. Discuss Solution: In free State, water is a liquid. When water gets freezes to 0 0 c degree Celsius, it will turn to ice, which is in solid form. When we heat water to 100  0 c, it vaporises into water vapours, which are the gaseous state of water; hence, it is said that water exists in all the three states. 2. Why water is considered a compound. Solution: Water is made up of two elements Hydrogen and Oxygen, which are in the ratio of 1:8 by mass; hence, water is considered as a compound. 3. a) Why does temperature in Mumbai and Chennai not fall as low as it does in Delhi. b) Give the properties of water responsible for controlling the temperature of our body. Solution: The temperature in Mumbai and Chennai does not fall as low as it does in Delhi because Mumbai and Chennai are on the shores of the sea. This increase the specific heat capacity of the area a