{"id":2664,"date":"2020-09-09T05:19:38","date_gmt":"2020-09-08T23:49:38","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=2664"},"modified":"2021-07-02T15:03:37","modified_gmt":"2021-07-02T09:33:37","slug":"kseeb-solutions-class-9-maths-chapter-13-ex-13-8","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/kseeb-solutions-class-9-maths-chapter-13-ex-13-8\/","title":{"rendered":"KSEEB Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8"},"content":{"rendered":"

Karnataka Board Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8<\/h2>\n

(Assume \u03c0 = \\(\\frac{22}{7}\\), unless stated otherwise)<\/p>\n

Question 1.
\nFind the volume of a sphere whose radius is
\n(i) 7 cm
\n(ii) 0.63 m
\nSolution:
\n(i) r = 7 cm, V = ?
\n\"KSSEB<\/p>\n

Question 2.
\nFind the amount of water displaced by a solid spherical ball of diameter
\n(i) 28 cm.
\n(ii) 0.21 m.
\nSolution:
\n(i) Diameter of solid spherical ball, diameter, d = 28 cm,
\n\u2234 radius, r = \\(\\frac{28}{2}\\) = 14 cm.
\nVolume of solid spherical ball, V = \\(\\frac{4}{3}\\) \u03c0r3<\/sup>.
\n\"KSSEB
\n\"KSSEB
\nAmount of water displaced by the ball = 0.00485 m3<\/sup>.<\/p>\n

Question 3.
\nThe diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3<\/sup> ?
\nSolution:
\nDiameter of metallic ball, d = 4.2 cm. density = 8.9 gm\/cm3<\/sup>
\nmass, m = ? d = 4.2 cm.
\n\"KSSEB
\n\u2234 V = 38.808 cm3<\/sup>.
\n\u2234 Mass = Density \u00d7 Volume
\n= 8.9 \u00d7 38.808
\n= 345.40 gm.<\/p>\n

Question 4.
\nThe diameter of the moon is approximately one-fourth of the diameter of the earth. What fraction of the volume of the earth is the volume of the moon?
\nSolution:
\nLet the diameter of earth be ‘d’ unit.
\n\"KSSEB
\n\"KSSEB
\n\u2234 Volume of Moon = \\(\\frac{1}{64}\\) \u00d7 Volume of Earth<\/p>\n

Question 5.
\nHow many litres of milk can a hemispherical bowl of diameter 10.5 cm hold?
\nSolution:
\nDiameter of a hemispherical bowl, d = 10.5 cm
\n\"KSSEB<\/p>\n

Question 6.
\nA hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank.
\nSolution:
\nIn a hemispherical tank,
\nInner radius, r1<\/sub> = 1 m
\nOuter radius, r2<\/sub> = 1 + 0.01 = 1.01 m (\u2235 1 cm = 0.01)
\n\u2234 Volume of hemispherical tank, V
\n= Volume of outer diameter – Volume of inner diameter.
\n\"KSSEB
\n\"KSSEB<\/p>\n

Question 7.
\nFind the volume of sphere whose surface area is 154 cm2<\/sup>.
\nSolution:
\nSurface area of sphere, 4\u03c0r2<\/sup> =154 cm2<\/sup>.
\nVolume of Sphere, V = ?
\nA = 4\u03c0r2<\/sup> = 154
\n\"KSSEB<\/p>\n

Question 8.
\nA dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of Rs. 498.96. If the cost of white-washing is Rs. 2.00 per square metre, find the
\n(i) inside surface area of the dome,
\n(ii) volume of the air inside the dome.
\nSolution:
\n(i) Cost of white-washing dome is Rs. 498.96
\nCost of white-washing is Rs. 2 per sq. metre.
\n\u2234 Surface Area = \\(\\frac{498.96}{2}\\) = 249.48 m2<\/sup>.<\/p>\n

(ii) Surface Area of hemisphere, V = 2\u03c0r2<\/sup>
\n\"KSSEB
\n\u2234 Inner volume of hemisphere dome, V
\n\"KSSEB<\/p>\n

Question 9.
\nTwenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S1<\/sub>. Find the
\n(i) radius r of the new sphere,
\n(ii) ratio of S and S1<\/sub>
\nSolution:
\n(i) Volume of 1 sphere, V = \\(\\frac{4}{3}\\)\u03c0r3<\/sup>
\nVolume of 27 solid sphere
\n= 27 \u00d7 \\(\\frac{4}{3}\\)\u03c0r3<\/sup>
\nLet r1<\/sub>is the radius of the new sphere.
\nVolume of new sphere = Volume of 27 solid sphere
\n\"KSSEB<\/p>\n

Question 10.
\nA capsule of medicine is in the shape of a sphere of diameter 3.5 mm. How much medicine (in mm3<\/sup>) is needed to fill this capsule?
\nSolution:
\nDiameter of capsule of medicine, d
\nd = 3.5 mm = \\(\\frac{7}{2}\\) mm.
\n\"KSSEB<\/p>\n

KSEEB Solutions for Class 9 Maths<\/a><\/h5>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Karnataka Board Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8 (Assume \u03c0 = , unless stated otherwise) Question 1. Find the volume of a sphere whose radius is (i) 7 cm (ii) 0.63 m Solution: (i) r = 7 cm, V = ? Question 2. Find the amount of water displaced by …<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/2664"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=2664"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/2664\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=2664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=2664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=2664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}