11. The area of the base of a rectangular tank is 6500 sq. cm and the volume of water contained in it is 2.6 cubic meters. The depth of water is ?

1. 1. 3.5 m

   
   
   

   2. 4 m

   
   
   

   3. 5 m

   
   
   

   4. 8 m

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let depth = D cm.
   Then, D x 6500 = 2.6 x 100 x 100 x 100

   Correct Option: B

   Let depth = D cm.
   Then, D x 6500 = 2.6 x 100 x 100 x 100
   ∴ D = (2.6 x 100 x 100 x 100) / 6500 cm
   = 400 cm = 4 cm
   

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12. In a shower, 5 cm of rain falls. The volume of water that falls on 2 hectare of ground, is ?

1. 1. 100 m³

   
   
   

   2. 1000 m³

   
   
   

   3. 10 m³

   
   
   

   4. 10000 m³

   
   
   

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1. View Hint View Answer Discuss in Forum

   Volume = Area x Thickness of rainfall

   Correct Option: B

   Volume = Area x Thickness of rainfall
   = 2 x 10000 x (5/100) m³
   = 1000 m³
   

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13. The volume of a cube is 512 cm³, Its surface area is ?

1. 1. 64 cm²

   
   
   

   2. 256 cm²

   
   
   

   3. 384 cm²

   
   
   

   4. 512 cm²

   
   
   

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1. View Hint View Answer Discuss in Forum

   ∵ a³ = 512 = 8 x 8 x 8
   ⇒ a = 8 cm
   ∵ Surface area = 6a²
   

   Correct Option: C

   ∵ a³ = 512 = 8 x 8 x 8
   ⇒ a = 8 cm
   ∵ Surface area = 6a²
   =[6 x (8)²] cm²
   =384 cm²
   

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14. The length of longest rod that can be placed in a room 20 m long, 16 m broad and 12 m high, is ?

1. 1. 20 m

   
   
   

   2. 16.4 m

   
   
   

   3. 48 m

   
   
   

   4. 28.2 m

   
   
   

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1. View Hint View Answer Discuss in Forum

   Length of the rod = √(20)² + (16)² + (12)² m
   

   Correct Option: D

   Length of the rod = √(20)² + (16)² + (12)² m
   = √800 m
   = 20√2 m
   = (20 x 1.41) m
   = 28.2 m

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15. The length of longest rod that can fit in a cubical vessel of side 10 cm, is ?

1. 1. 10 cm

   
   
   

   2. 10√2

   
   
   

   3. 10√3

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   Longest rod = √(10)² + (10)² + (10)² cm

   Correct Option: C

   Longest rod = √(10)² + (10)² + (10)² cm
   =√300 cm
   =10√3 cm
   

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