The curved surface area of a right circular cone of height 15 cm and base diameter 16 cm is

**A. ** 60*π* cm^{2}

**B. ** 68*π* cm^{2}

**C. ** 120*π* cm^{2}

**D. ** 136*π* cm^{2}

**Answer : ****Option D**

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If two solid hemispheres of same base radius r units are joined together along their bases, then curved surface area of this new solid is

**A. ** 4*πr*^{2}
sq. units

**B. ** 6*πr*^{2} sq.
units

**C. ** 3*πr*^{2}
sq. units

**D. ** 8*πr*^{2} sq.
units

**Answer : ****Option A**

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The height of a right circular cone whose radius is 5 cm and slant height is 13 cm will be

**A. ** 12 cm

**B. ** 10 cm

**C. ** 13 cm

**D. ** 5 cm

**Answer : ****Option A**

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If the radius of the base of a right circular cylinder is halved keeping the same height, then the ratio of the volume of the cylinder thus obtained to the volume of original cylinder is

**A. ** 1:2

**B. ** 1:4

**C. ** 1:6

**D. ** 1:8

**Answer : ****Option B**

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The total surface area of a cylinder whose radius is 1/3 of its height is

**A. **

**B. **

**C. **

**D. **

**Answer : ****Option C**

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In a hollow cylinder, the sum of the external and internal radii is 14 cm and the width is 4 cm. If its height is 20 cm, the volume of the material in it is

**A. ** 5600*π* cm^{3}

**B. ** 11200*π* cm^{3}

**C. ** 56*π* cm^{3}

**D. ** 3600*π* cm^{3}

**Answer : ****Option B**

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If the radius of the base of a cone is tripled and the height is doubled then the volume is

**A. ** made 6 times

**B. ** made 18 times

**C. ** made 12 times

**D. ** unchanged

**Answer : ****Option B**

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The total surface area of a hemi-sphere is how much times the square of its radius.

**A. ** π

**B. ** 4π

**C. ** 3π

**D. ** 2π

**Answer : ****Option C**

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A solid sphere of radius x cm is melted and cast into a shape of a solid cone of same radius. The height of the cone is

**A. ** 3*x* cm

**B. ** *x* cm

**C. ** 4*x* cm

**D. ** 2*x* cm

**Answer : ****Option C**

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A frustum of a right circular cone is of height 16cm with radii of its ends as 8cm and 20cm. Then, the volume of the frustum is

**A. ** 3328*π* cm^{3}

**B. ** 3228*π* cm^{3}

**C. ** 3240*π* cm^{3}

**D. ** 3340*π* cm^{3}

**Answer : ****Option A**

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