Ohm's law defines the fundamental relationship among which three electrical quantities used in circuit analysis and design?

Difficulty: Easy

Correct Answer: voltage, current, and resistance

Explanation:

Introduction:Ohm's law is the cornerstone of basic circuit theory. It relates voltage (the electrical potential difference), current (the rate of charge flow), and resistance (opposition to current) with a simple proportionality used in virtually every DC and many AC calculations.

Given Data / Assumptions:

  • Applies to ohmic (linear) resistive elements over the operating region of interest.
  • Ambient conditions and temperature kept within normal ranges where resistance is approximately constant.

Concept / Approach:The relationship is V = I * R. If any two of the quantities are known, the third can be solved directly. This enables sizing of resistors, predicting currents, or determining safe supply voltages.

Step-by-Step Solution:Start from V = I * RSolve for current: I = V / RSolve for resistance: R = V / IApply proportionality: doubling V at fixed R doubles I; doubling R at fixed V halves I.

Verification / Alternative check:Lab measurements with a resistor and variable DC supply show linear I–V plots passing through the origin, confirming the proportionality embodied in Ohm's law.

Why Other Options Are Wrong:

  • voltage, current, and time / resistance, time, and current: Time is not part of the Ohm's law identity.
  • power, current, and resistance: Power relates via P = V * I = I^2 * R = V^2 / R, which derives from Ohm's law but is not the law itself.
  • charge, flux, and inductance: These relate to other electromagnetic concepts, not Ohm's law.

Common Pitfalls:

  • Applying Ohm's law to non-linear devices (diodes, lamps) where V–I is not linear.
  • Ignoring temperature effects that change R significantly in some materials.

Final Answer:voltage, current, and resistance

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