Question

Study the figure on the side and answer the questions:-

(a) What is known as Sial ? How deep is the area marked by Sial ? 

(b) What role does Sima play ? 

(c) Why is the expression ‘Nife’ so called ? 

(d) Which layer is responsible for earth’s magnetic field ? Why? 

(e) What happens to the continents if there is an earthquake?

Answer 1

(a) Sial is the upper layer or crust of the earth. The name Sial is based on the excess of Silica and Aluminium. The depth of Sial is 60 km. 

(b) Sima is the second layer of earth which gives support to the ocean beds. There is the excess of Silica and Magnesium. 

(c) ‘Nife’ means Nickel (Ni) and Iron (Fe) due to the majority of Nickel and Iron in the core, 

(d) Core of earth is responsible for earth’s magnetic field because it is composed of iron and nickel which is responsible for earth’s magnetism. Magnetic field is oriented towards North and South Poles. 

(e) Several drastic changes may occur during the earthquake. It depends on the intensity of the earthquake. If intensity is 8 or more buildings may break up, casualties and major changes on the landforms as broad breaking gaps, origin or disappearing of several small islands.