ESIC Nursing Officer - 2019 (Shift-2)
Non Nursing Subjects
Hard

The curved surface area of a right circular cylinder of base radius R, in terms of volume V, is:

Appeared in: ESIC Nursing Officer - 2019 (Shift-2)

Explanation

  • The volume (V) of a cylinder is V = π * R² * h, and the curved surface area (CSA) is CSA = 2 * π * R * h.
  • To express CSA in terms of V and R, first isolate height (h) from the volume formula: h = V / (π * R²).
  • Substitute this expression for h into the CSA formula: CSA = 2 * π * R * [V / (π * R²)].
  • Simplifying the expression by canceling π and one R term gives CSA = 2V / R.

Why Other Options Were Wrong

  • Option A: This option incorrectly multiplies V and R. The derivation shows that R should be in the denominator.
  • Option B: This option is missing the factor of 2. The formula for CSA includes a '2' (from 2 * π * R * h), which remains after simplification.
  • Option C: This option incorrectly multiplies V by R instead of dividing. This would imply that as the radius increases (for a fixed volume), the surface area also increases, which is incorrect.

Related Visual

Visual explanation — Related Visual
  • Visual 1: Diagram - An annotated diagram of a right circular cylinder, clearly labeling the radius (R), height (h), base area, and curved surface area. This helps visualize the components used in the formulas.
  • Visual 2: Infographic - A flowchart showing the step-by-step derivation: Start with V and CSA formulas -> Isolate h from V formula -> Substitute h into CSA formula -> Simplify to get the final expression. This reinforces the logical process.
Clinical Relevance
  • Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Relationship between Volume and Surface Area of a Cylinder as background academic context rather than a clinical decision trigger.
  • While this is a mathematics question, understanding geometric relationships is foundational for many scientific and medical calculations, such as calculating the volume of a vial or the surface area of a cylindrical cast.
  • This skill in algebraic manipulation is crucial for dosage calculations where formulas must be rearranged to solve for an unknown variable.
  • What if the question asked for the Total Surface Area (TSA) in terms of V and R? The process would be similar: TSA = 2 * π * R * (h + R) = 2 * π * R * h + 2 * π * R². Substituting h = V / (π * R²) gives TSA = 2V/R + 2 * π * R², demonstrating how different properties are related.
How to Approach the Question
  • Identify the key geometric shape: a right circular cylinder.
  • List the standard formulas associated with this shape: Volume (V = π * R² * h) and Curved Surface Area (CSA = 2 * π * R * h).
  • Analyze the goal: Express CSA using only the variables V and R. This means the variable 'h' must be eliminated.
  • Use algebraic substitution. Rearrange the volume formula to solve for the variable you want to eliminate (h).
  • Substitute the resulting expression for 'h' into the CSA formula.
  • Simplify the final algebraic expression to match one of the given options.
Concept Tested & Keywords
  • Concept Tested: Relationship between Volume and Surface Area of a Cylinder
  • Stem keywords: Curved surface area, right circular cylinder, base radius R, volume V
  • Lead-in keywords: BEST, MOST RELEVANT CLUE

Question ID

QGzSdqxiCmSnxkuo_k9mJ2

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