In the metric system of measurement, 1 cup is usually considered as ___ ml.

Appeared in: UPUMS Nsg officer-2023

Explanation

In standard medical and measurement systems, 1 cup is equivalent to 240 milliliters (mL).
This conversion is derived from the fact that 1 US fluid ounce is approximately 30 mL, and a standard cup contains 8 fluid ounces (8 oz × 30 mL/oz = 240 mL).
This specific conversion is critical for accurate medication administration, especially liquid formulations, and for precise tracking of a patient's fluid intake and output (I&O).

Option A: While some non-standard cups or glasses might hold 200 mL, this is not the accepted conversion in a clinical or medical context. Using this value would lead to inaccurate measurements.
Option C: 150 mL is the standard equivalent for 5 fluid ounces or 10 tablespoons, which is substantially smaller than a standard 8-ounce cup.
Option D: 190 mL does not correspond to any standard household or metric conversion unit used in healthcare.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Household to Metric Measurement Conversion as background academic context rather than a clinical decision trigger.
Precise conversion from household units (like cups) to metric units (mL) is a fundamental patient safety measure, preventing dosage errors in liquid medications and ensuring accurate fluid balance monitoring.
Nurses must educate patients and their families to use standardized measuring devices (like oral syringes or marked medicine cups) instead of household spoons or cups, which can vary greatly in size.
What if? If a nurse incorrectly assumes a cup is 200 mL instead of 240 mL for a patient on a strict 1500 mL daily fluid restriction, the patient could inadvertently consume an extra 160 mL over four 'cups' of fluid, potentially leading to fluid overload in a cardiac or renal patient.

How to Approach the Question

First, identify the core of the question. It's asking for a standard conversion between a household unit (cup) and a metric unit (mL).
Recognize this as a factual recall question, which is common in nursing fundamentals and pharmacology to ensure safety in practice.
Recall the key conversion factors used in healthcare. The most fundamental ones are 1 tsp = 5 mL, 1 tbsp = 15 mL, and 1 oz = 30 mL.
Remember that a standard measuring cup is defined as 8 fluid ounces.
Perform the calculation: 8 ounces × 30 mL/ounce = 240 mL.
Scan the options and select the one that matches your calculated and recalled answer.

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 3 p. 141-143

E6 Nursing Fundamentals Taylor p. 848-850

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Attempt every question from this paper in a timed mock, then review the full solution for each one.