Volume and Surface Area of Solid Figures


  1. A cylindrical jar, whose base has a radius of 15 cm, is filled with water upto a height of 20 cm, A solid iron spherical ball of radius 10 cm is dropped in the jar to submerge completely in water. Find the increase in the level of water (in cm). ?









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    Let level of water will be increased by h cm
    π x (15)2 x h = (4/3)π(10)3

    Correct Option: D

    Let level of water will be increased by h cm
    π x (15)2 x h = (4/3)π(10)3
    ∴ h = [(4/3) x 10 x 10 x 10] / [15 x 15]
    = 525/27 cm


  1. Water flows at the rate of 10 m/min from a cylindrical pipe 5 mm in diameter. How long will it take to fill up a conical vessel whose diameter at the base is 40 cm and depth is 24 cm ?









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    Given, radius of pipe 5/2 x 10 = 5/20 cm [∵ 1 cm = 10 mm]
    Height of pipe = 1000 cm
    Radius of vessel = 20 cm and height = 24 cm
    Volume of water flow in one minute from cylindrical pipe = π (5/20)2 x 1000
    = 125/2 π cm3
    and volume of conical vessel = 1/3 π(20)2 x 24 = 3200π cm3
    ∴ Required time = (3200π x 2) / 125π

    Correct Option: A

    Given, radius of pipe 5/2 x 10 = 5/20 cm [∵ 1 cm = 10 mm]
    Height of pipe = 1000 cm
    Radius of vessel = 20 cm and height = 24 cm
    Volume of water flow in one minute from cylindrical pipe = π (5/20)2 x 1000
    = 125/2 π cm3
    and volume of conical vessel = 1/3 π(20)2 x 24 = 3200π cm3
    ∴ Required time = (3200π x 2) / 125π
    = 511/5 or 51 min 12 s



  1. In a shower, 10 cm of rain falls, What will be the volume of water that falls on 1 hect area of ground ?









  1. View Hint View Answer Discuss in Forum

    1 hec = 10000 m3
    Volume of water = Base area x Height

    Correct Option: C

    1 hec = 10000 m3
    Volume of water = Base area x Height
    = (10000 x 10)/100 = 1000 m3


  1. The radius of a sphere and a right circular cylinder are equal and their curved surface areas are also equal. The ratio of their volumes is ?









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    Given, 4πr2 = 2πrh
    ∴ h = 2r
    Now, required ratio
    = 4/3πr3 : πr2h

    Correct Option: B

    Given, 4πr2 = 2πrh
    ∴ h = 2r
    Now, required ratio
    = 4/3πr3 : πr2h
    = 4r : 3h
    = 4r : 6r [ ∴ h = 2r]
    = 2 : 3



  1. How many spherical bullets can be made out of a solid cube whose edge measures 44 cm, each bullet being 4 cm in diameter ?









  1. View Hint View Answer Discuss in Forum

    Volume of 1 bullet = 4/3π(2)3 = (32/3 x 22/7) cm3
    Volume of the cube = (44)3

    Correct Option: B

    Volume of 1 bullet = 4/3π(2)3 = (32/3 x 22/7) cm3
    Volume of the cube = (44)3
    ∴ Number of bullets = Volume of solid/Volume of 1 bullet
    = (44)3 x 3 x 7 / 32 x 22 = 2541