Geography Class 7th MCQs=340

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• There are three main layers of the earth. 1) Core        2) Mantle        3) Crust   
• Core:
• Core is a ball like structure which is present in the centre of the earth. It is divided in to two parts.
• a) Inner core
• b) Outer core
• Inner core: Inner core is hard and solid.
  
• It is 1250km thick and nearly 4300⁰C hot.
• Outer core: The outer core is in semi liquid form.
• It is 2250km thick and about 3700⁰C hot.
• Mantle:
• It is the second layer of the earth.
• It is about 3000km thick.
  
• Mantle layer is composed of Iron, Silicon and Magnesium elements.
• Temperature of the upper portion of the mantle is 870⁰C that reaches up to 3600⁰C in the lower portion.
• Crust:
  
• It is the lightest and thinnest layer of the earth.
• It is mostly composed of Silicon and Aluminum element.
• 20 to 70 km average thickness at continents, while 5 to 10km at ocean.
• Faults: The crust of the earth is broken in different places. The broken lines are called faults.
• There are three types of Faults. 1) Normal Fault  2) Reverse Fault       3) Lateral Fault         
  
• Important faults of Pakistan:
• Main Karakorum Fault: It is located in Northern areas of Pakistan, Kashmir and Gilgit Bultistan.
• Jhelum Fault: It’s run through Jhelum District and Rawalpindi.                    
  
• Kalabagh Fault: It passes through Kalabagh town, District Mianwali and Jhelum.
• Chaman Fault: It is found in Baluchistan and goes through Chaman.
• Salt Range thrust: It passes through Chakwal, Jhelum and many other areas.           
  
• In December 2004, an earthquake came in the Western coast of Sumatra (Indonesia). Its intensity on Richter scale was 9.2 on reaching the coast the waves got a height of more than 30 meter, nearly 230,000 people died.
• The coastal areas of Pacific Ocean (بحرالکائل ) are called “Ring of Fire” (آگ کا گولہ).
  
• Mount Saint Hallen, after 120 years of dormancy ejected lava on 20^th March, 1980. It caused a huge economic and human loss.

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MCQs                                                                       

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There are …………..main layers of Earth.
a) 2     

b) 3                 

c) 4     

d) 5

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The property of the big three layers of the earth resemble the………
a) Onion                     

b) Ball             
c)  Tomato                  

d) Egg

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Which of the following is resembles the yolk of an egg?
a) Core                                   

b) Crust
c) Mantle                    

d) none of these

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Core is divides in how many parts?
a) 2     

b) 3                 

c) 4     

d) 5

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