Exercise 12.1

A metallic spherical shell of internal and external diameters 4 cm and 8 cm, respectively is melted and recast into the form a cone of base diameter 8cm. The height of the cone is (A) 12cm (B) 14cm (C) 15cm (D) 18cm

(B) 14cm Volume of circular shell = Volume of cone recast by liquefying For Spherical Shell, Inside measurement, d1 = 4 cm Inside range, r1 = 2 cm [ as range = 1/2 diameter] Outer measurement, d2 =...

read more

A hollow cube of internal edge 22cm is filled with spherical marbles of diameter 0.5 cm and it is assumed that 1/8 space of the cube remains unfilled. Then the number of marbles that the cube can accommodate is (A) 142296 (B) 142396 (C) 142496 (D) 142596

(A) 142296   As indicated by the inquiry,   Volume of block =223=10648cm3   Volume of block that stays unfilled \[=1/8\times 10648=1331cm3\]   volume involved by circular marbles...

read more

A cone is cut through a plane parallel to its base and then the cone that is formed on one side of that plane is removed. The new part that is left over on the other side of the plane is called (A) a frustum of a cone (B) cone (C) cylinder (D) sphere

(A) a frustum of a cone At the point when a cone is isolated into two sections by a plane through any point on its pivot corresponding to its base, the upper and lower parts got are cone and a...

read more

Choose the correct answer from the given four options: A cylindrical pencil sharpened at one edge is the combination of (A) a cone and a cylinder (B) frustum of a cone and a cylinder (C) a hemisphere and a cylinder (D) two cylinders.

(A) a cone and a cylinder The Nib of a sharpened pencil = conical shape The rest of the part of a sharpened pencil = cylindrical Therefore, a pencil is a combination of cylinder and a cone.

read more