Question

of the portion cut off and the remaining portion of the sphere.
13. On the curved surface of the axis of a globe with the length of 14 cm. radius, two circular
holes are made each of which has the length of radius 0.7 cm. Let us calculate the area of
metal sheet surrounding its curved surface.
14. Let us write by calculating how many marbles with lengths of 1 cm. radius may be formed
by melting a solid sphere of iron having 8 cm length of radius.
15. Very short answer type question (V.S.A.)
(A) (M.C.Q.):
(i) The volume of a solid sphere having the radius of 2r units length is
(a) 32mcubic unit (b) 165 cubic unit (c) SA cubic unit (d) 64 cubic unit
(i) If the ratio of the volumes oftwo solidspheresis 1:8, the ratio of their curved surface areas is
(a) 1:2 (b) 1:4 (c) 1:8 (d) 1:16
(ii) The whole surface area of a solid hemisphere with length of 7 cm radius is
(a) 588 a sq cm. (b) 392 it sq cm. (c) 147 sq cm. (d) 9870 sq cm.
(iv) If the ratio of curved surface areas of two solid spheres is 16:9, the ratio of their volumes is
(a) 64:27 (b) 4:3 (c) 27:64 (d) 3:4​

Answer 1

Answer:

On the curved surface of the axis of a globe with the length of 14 cm. radius, two circular holes are made each of which has the length of radius 0.7 cm. Let us calculate the area of metal sheet surrounding its curved surface.

Class 10th

West Bengal Board - Mathematics

12. Sphere

Answer :

Given:

Radius of globe(spherical), R = 14cm

Radius of holes, r = 0.7cm

Formula used: