Difficulty: Easy
Correct Answer: ampere
Explanation:
Introduction / Context:
Electrical engineering relies on a small set of SI units. Recognizing which quantity each unit measures helps when interpreting datasheets and equations such as Ohm’s law and power relations.
Given Data / Assumptions:
Concept / Approach:
The ampere (A) is the SI base unit for electric current. By contrast, the volt is a derived unit (J/C), the ohm is derived (V/A), and the watt is derived (J/s = V*A). Thus, only “ampere” correctly answers the prompt.
Step-by-Step Solution:
List candidates: volt, watt, ampere, ohm.Identify base vs derived: ampere is base; others are derived.Select “ampere.”
Verification / Alternative check:
Ohm’s law I = V/R uses ampere directly for current. Power P = V * I shows watt as derived from volt and ampere.
Why Other Options Are Wrong:
(a) Volt measures electric potential difference. (b) Watt measures power. (d) Ohm measures resistance. None are base units for current.
Common Pitfalls:
Confusing commonly seen units with base units; many electrical units are derived from A, s, kg, m, and K.
Final Answer:
ampere.
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