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प्रश्न
A solid sphere of radius 3 cm is melted and then cast into small spherical balls, each of diameter 0.6 cm. Find the number of balls obtained.
उत्तर
Radius of solid sphere = 3 cm
volume of the sphere`=4/3pir^3=4/3pixx3xx3xx3 "cm"^3`
Radius of each new ball= 0.3 cm
Volume of each new ball`= 4/3pir^3 = 4/3pixx3/10xx3/10xx3/10 "cm"^3`
Total number of balls `=(4/3pixx3xx3xx3)/(4/3pixx3/10xx3/10xx3/10) =1000`
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Assertion (A)
The curved surface area of a cone of base radius 3 cm and height 4 cm is 15π cm2.\
Reason (R)
Volume of a cone = πr2h
- Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).
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- Assertion (A) is true and Reason (R) is false.
- Assertion (A) is false and Reason (R) is true.
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If the length of the diagonal of a cube is `5sqrt(3)` cm, find the total surface area.
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So, `square` = `5sqrt(3)`
⇒ Side = `square`
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Hence, the total surface area is `square`.
