Ohm's Law: Linear I-V Relationship for Fixed Resistor

Steps:

• Apply Ohm's Law: I = V/R, where R is constant for a fixed resistor.
• Plot I (y-axis) versus V (x-axis): I is directly proportional to V.
• Expect a straight line through the origin with slope 1/R.
• Identify graph D as the straight line passing through (0,0).

Why D is correct:

• For an ohmic device like a fixed resistor, current varies linearly with voltage per Ohm's Law, yielding a straight-line graph through the origin.

Why the others are wrong:

• A: Straight line not through origin implies non-zero current at zero voltage, violating Ohm's Law.
• B: Curved line suggests non-linear resistance, not true for a fixed resistor.
• C: Horizontal line indicates constant current regardless of voltage, contradicting I = V/R.

Final answer: D