Question 21 (OR 2 nd Β question)
A solid sphere of radius 3 cm is melted and then recast into small spherical balls each of diameter 0.6 cm. Find the number of balls




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CBSE Class 10 Sample Paper for 2019 Boards
Last updated at Oct. 1, 2019 by Teachoo
Question 21 (OR 2 nd Β question)
A solid sphere of radius 3 cm is melted and then recast into small spherical balls each of diameter 0.6 cm. Find the number of balls
Question 21 (OR 2nd question) A solid sphere of radius 3 cm is melted and then recast into small spherical balls each of diameter 0.6 cm. Find the number of balls Since the big sphere is melted to make balls Volume of big sphere = Volume of balls Volume of big sphere = Number of balls Γ Volume of 1 ball β΄ Number of balls = (ππππ’ππ ππ πππ π πβπππ)/(ππππ’ππ ππ 1 ππππ) Volume of big sphere Radius = 3 cm Volume of sphere = 4/3 π(π)3 = 4/3ΓπΓ(3)^3 = 4/3ΓπΓ27 Volume of 1 ball Diameter = 0.6 cm Radius = 0.6/2 = 0.3 cm = 3/10 cm Volume of 1 ball = 4/3 π(π)3 = 4/3ΓπΓ(3/10)^3 = 4/3ΓπΓ27/1000 Now, Number of balls = (ππππ’ππ ππ πππ π πβπππ)/(ππππ’ππ ππ 1 ππππ) = (4/3 Γ π Γ 27" " )/(4/3 Γ π Γ 27/1000) = 27" " /( 27/1000) = 27" " /27 Γ 1000 = 1000 β΄ Number of balls is 1000