Difficulty: Easy
Correct Answer: Incorrect — resistance value and power rating are independent parameters
Explanation:
Introduction / Context:
Resistor datasheets list at least two fundamentally different specifications: resistance value (ohms) and power rating (watts). Confusing these leads to poor part selection and overheating in products. The question probes whether the two are directly proportional, which they are not.
Given Data / Assumptions:
Concept / Approach:
Resistance is set by material resistivity, geometry, and construction; power rating is set by how much heat the body can dissipate while staying within safe temperature rise. You can buy a 10 Ω resistor rated at 1/4 W or 10 W; the ohmic value does not force a specific watt rating. Conversely, two resistors of the same wattage can have wildly different resistances.
Step-by-Step Solution:
Verification / Alternative check:
Compare catalog parts: the same 1 kΩ value is offered in 1/8 W, 1/4 W, 1/2 W, 1 W, etc., illustrating independence of specs.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming higher resistance dissipates more heat; in fact, dissipation depends on the applied V or I and the environment.
Final Answer:
Incorrect — resistance and watt rating are independent specifications.
Discussion & Comments