Question

If numerical value of curved surface area of a solid sphere is three times of its volume, the length of its radius is
A. 1 unit
B. 2 unit
C. 3 unit
D. 4 unit

Answer 1

Let the radius of the sphere = r units
`therefore` curved surface area of the sphere `=4pir^(2)` sq-units
`therefore` the volume of the sphere `=(4)/(3)pir^(3)` cubic-units
As per questions, `4pir^(2)=3xx(4)/(3)pir^(3)` or, `4pir^(2)=4pir^(3) rArr1=r rArrr=1`
`therefore` radius =1unit
`therefore` radius =1 unit
`therefore` (a) is correct.