Select the correct Ohm’s law rearrangement: which formula gives current I when voltage V and resistance R are known (identify the valid relationship)?
-
AI = V R
-
BI = R/V
-
CV = I R
-
DI = V/R
Answer
Correct Answer: I = V/R
Explanation
Introduction / Context:Ohm’s law relates voltage, current, and resistance. Being able to rearrange this relationship is vital when solving for a specific variable in circuit problems or lab measurements.
Given Data / Assumptions:
- Canonical form: V = I * R.
- We need I in terms of V and R.
- Assume ideal linear resistor behavior.
Concept / Approach:
From V = I * R, divide both sides by R to isolate current. Ensure the units are consistent: volts divided by ohms yields amperes, confirming dimensional correctness.
Step-by-Step Solution:
Start with V = I * R.Divide both sides by R: V / R = I.Reorder: I = V / R.Verification / Alternative check:
Unit check: V / Ω = A, which is the SI unit for current.
Why Other Options Are Wrong:
I = V R multiplies instead of divides; I = R / V inverts the correct ratio; V = I R is true but solves for V, not I.
Common Pitfalls:
Mixing up division/multiplication when isolating variables; not checking units as a safeguard.
Final Answer:
I = V/R