Ohm S Law

Step 1: Understanding the graph of and .
The graph between voltage and current for a conductor is a straight line, and its slope represents the resistance of the conductor. The slope is given by the tangent of the angle the graph makes with the horizontal axis (which is voltage).
Step 2: Applying the formula.
From Ohm's law, , where is the resistance. If the graph between and is a straight line, the slope . The angle between the line and the horizontal axis gives the tangent of the angle as . Therefore, the resistance is given by .
Step 3: Conclusion.
Thus, the resistance of the conductor is , which is the inverse of the tangent of the angle.

Step 1: Formula for Resistance.
The formula for the resistance of a conductor is given by: Where: - is the resistance - is the resistivity - is the length of the conductor - is the cross-sectional area
Step 2: Elimination of options.
- (A) : This is incorrect because the formula for resistance involves , not .
- (B) : Incorrect, this would result in a reversed formula.
- (C) : Incorrect, as the formula involves , not .
- (D) : Incorrect, this expression does not correspond to the correct formula for resistance.
Step 3: Conclusion.
Therefore, the correct formula for resistance is .

Step 1: Understanding the formula for power in an electric circuit.
The power in an electric circuit can be calculated using the formula: where is the voltage across the resistor and is the resistance of the circuit. This formula is derived from Ohm's law ( ) and the basic power formula ( ). By substituting , we get: Step 2: Conclusion. Thus, the correct answer is .