Question : If the radius of a sphere is increased by 2 cm, then its surface area increases by 352 cm2. The radius of the sphere initially was: (use $\pi =\frac{22}{7}$)
Option 1: 4 cm
Option 2: 5 cm
Option 3: 3 cm
Option 4: 6 cm
New: SSC CHSL tier 1 answer key 2024 out | SSC CHSL 2024 Notification PDF
Recommended: How to crack SSC CHSL | SSC CHSL exam guide
Don't Miss: Month-wise Current Affairs | Upcoming government exams
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: 6 cm
Solution : Let the initial radius be $r$ Area before increment $= 4\pi r^2$ Given: After increasing the radius by 2 cm, the area is increased by = 352 cm$^2$ According to the question, $4\pi r^2 + 352 = 4\pi (r+2)^2$ ⇒ $4\pi r^2 + 352 = 4\pi (r^2+4r+4)$ ⇒ $4\pi r^2 + 352 = 4\pi r^2+16\pi r+16\pi$ ⇒ $352 = 16\pi(1+r)$ ⇒ $\frac{352}{16\pi} = 1+r$ ⇒ $\frac{352×7}{16×22} = 1+r$ ⇒ $7 = 1+r$ ⇒ $r = 6$ cm Hence, the correct answer is 6 cm.
Candidates can download this e-book to give a boost to thier preparation.
Result | Eligibility | Application | Admit Card | Answer Key | Preparation Tips | Cutoff
Question : Find the surface area of a sphere whose radius is 3.5 cm. Use $(\left.\pi=\frac{22}{7}\right)$.
Question : The total surface area of a cylinder whose radius is 6 cm and height is 8 cm is: (Use $\pi=\frac{22}{7}$)
Question : The radius and slant height of a cone are in the ratio 5 : 7. If its curved surface area is 1347.5 cm2, find its radius. $\mathrm{(Use ~\pi =\frac{22}{7})}$
Question : The total surface area of a solid hemisphere of diameter 14 cm is (use $\pi=\frac{22}{7}$ ):
Question : Find the volume of a solid sphere whose diameter is 42 cm. (Use $\pi=\frac{22}{7}$)
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile