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Shaping of the Earth’s Surface: CBSE Class 9 Geography practice questions

Practise 50 questions on Shaping of the Earth’s Surface, free, with an explanation for each answer.

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Sample questions

This slab of the Earth's outer layer carries both a continent and part of an ocean floor. What kind of tectonic plate is it?

One slab of the Earth's outer layer carrying land and sea
  1. Oceanic plate
  2. Mixed plate
  3. Continental plate
  4. Transform plate
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B. Mixed plate

Continental plates carry continents, oceanic plates carry ocean floors and mixed plates carry both. The chapter names seven major plates: Pacific, Eurasian, African, North American, South American, Indo-Australian and Antarctic. There is no 'transform plate'; transform is a type of plate boundary.

The Earth's radius is about 6375 km6375\ \text{km}. The inner core's radius is about 1250 km1250\ \text{km}. Roughly how deep below the surface does the inner core begin?

A cut-away of the Earth with its layers shown as rings
  1. 7625 km7625\ \text{km}
  2. 1250 km1250\ \text{km}
  3. 5125 km5125\ \text{km}
  4. 3475 km3475\ \text{km}
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C. 5125 km5125\ \text{km}

Depth to the top of the inner core = radius of Earth − radius of inner core: 6375−1250=5125 km6375 - 1250 = 5125\ \text{km} 76257625 km comes from adding instead of subtracting, 12501250 km is just the inner core's radius (measured from the centre), and 34753475 km comes from subtracting the mantle's thickness (2,900 km) by mistake.

A plate moves slowly at 4 cm4\ \text{cm} per year. How long will it take to move 1 km?

A slab of land sliding slowly over a soft hot layer, beside a ruler
  1. 250 years
  2. 4,00,000 years
  3. 2,500 years
  4. 25,000 years
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D. 25,000 years

1 km=1000 m=1,00,000 cm1\ \text{km} = 1000\ \text{m} = 1{,}00{,}000\ \text{cm}. Time=1,00,000 cm4 cm per year=25,000 years\text{Time} = \dfrac{1{,}00{,}000\ \text{cm}}{4\ \text{cm per year}} = 25{,}000\ \text{years} 250 years comes from taking 1 km as only 1000 cm, 2,500 years from taking it as 10,000 cm, and 4,00,000 years from multiplying instead of dividing.

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