Let the radius of the sphere initially be \(r\) units. Then the new radius becomes \(2r\) units.
The original curved surface area of the sphere: \[ = 4\pi r^2 \ \text{square units} \] New curved surface area: \[ = 4\pi (2r)^2 = 4\pi \times 4r^2 = 16\pi r^2 \ \text{square units} \] Increase in area: \[ = 16\pi r^2 - 4\pi r^2 = 12\pi r^2 \ \text{square units} \] Percentage increase: \[ = \frac{12\pi r^2}{4\pi r^2} \times 100 = 300\% \] (ANSWER)