RRB Group D Mock Test 01 – Question 35

Question:

A cylinder of height 72 cm and base radius 16 cm is melted to form a sphere. Find the radius of the sphere.

ऊँचाई 72 सेमी और आधार त्रिज्या 16 सेमी वाले एक बेलन को पिघलाकर एक गोला बनाया जाता है। गोले की त्रिज्या ज्ञात कीजिए।

Options :

  • a) 26 cm
  • b) 20 cm
  • c) 22 cm
  • d) 24 cm
  • a) 26 सेमी
  • b) 20 सेमी
  • c) 22 सेमी
  • d) 24 सेमी

correct answer : d)

Explanation :

Volume of cylinder = π × r² × h = π × (16)² × 72 = π × 256 × 72 = 18,432π.
Volume of sphere = (4/3) × π × R³.
(4/3) × π × R³ = 18,432π ⇒ R³ = (18,432 × 3) / 4 = 13,824 ⇒ R = ∛13,824 = 24 cm.

बेलन का आयतन = π × r² × h = π × (16)² × 72 = π × 256 × 72 = 18,432π।
गोले का आयतन = (4/3) × π × R³.
(4/3) × π × R³ = 18,432π ⇒ R³ = (18,432 × 3) / 4 = 13,824 ⇒ R = ∛13,824 = 24 सेमी।

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