Component terminology check: Is a rheostat considered a type of variable resistor used to adjust current or resistance?
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ACorrect — a rheostat is a variable resistor (typically 2-terminal use of a potentiometer).
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BIncorrect — a rheostat is a fixed resistor with a high power rating only.
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CIncorrect — a rheostat is a type of inductor used for current control.
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DIncorrect — a rheostat is only a voltage divider and cannot vary resistance.
Answer
Correct Answer: Correct — a rheostat is a variable resistor (typically 2-terminal use of a potentiometer).
Explanation
Introduction / Context:Rheostats and potentiometers are common adjustable resistive components. Understanding their definitions and typical connections avoids specification and wiring errors in labs and industry.
Given Data / Assumptions:
- Rheostat: high-power adjustable resistor, commonly wired as a 2-terminal device.
- Potentiometer: 3-terminal resistor with a wiper; can be used as voltage divider or variable resistor.
- Goal: determine whether a rheostat counts as a variable resistor.
Concept / Approach:A variable resistor is any resistor whose resistance can be adjusted. A potentiometer is a variable resistor with three terminals; when two terminals are used (one end and the wiper), it functions as a rheostat. Many rheostats are physically similar to potentiometers but designed for higher current/power. Therefore, a rheostat is indeed a type of variable resistor.
Step-by-Step Solution:
Define variable resistor: a component with adjustable resistance.Define rheostat: 2-terminal adjustable resistor (often one end plus wiper of a potentiometer), typically higher power.Conclude: a rheostat is a variable resistor.Verification / Alternative check:Handbooks specify wiring a potentiometer as a rheostat by tying one end to the wiper, leaving two terminals to vary series resistance in a circuit.
Why Other Options Are Wrong:
- Fixed high-power resistor (option b) lacks adjustability.
- Inductor (option c) is a different passive component.
- “Only a voltage divider” (option d) ignores the common 2-terminal rheostat configuration.
Common Pitfalls:Assuming “potentiometer” and “rheostat” are interchangeable without noting connection method and power rating. Always check the application and required wattage.
Final Answer:Correct — a rheostat is a variable resistor.