Correct Answer - Option 1 : 5 cm

**Given:**

Radius increased by = 4 cm

Difference between increased surface area and initial surface area of the sphere = 704 cm^{2}

**Formula used,**

Area of the sphere = 4πr^{2}

Where,

r → Radius of sphere

**Calculation**

Area of the sphere = 4πr2

According to the question,

4π(r + 4)^{2} – 4πr^{2} = 704

⇒ 4 × 22/7 × [(r + 4)^{2} - r^{2}] = 704

⇒ (r + 4)^{2} - r^{2} = 56

⇒ r^{2} + 16 + 8r - r^{2} = 56

⇒ 8r = 40

⇒ r = 5

**∴ The radius = 5 cm **