Electromagnetism

The capacitance of a parallel plate capacitor is determined by its physical geometry, given by the formula C = epsilon_0 * A / d, meaning it depends on the plate area and plate separation. Options A and B are incorrect because while capacitance relates charge to voltage (C = Q/V), these variables do not change the intrinsic capacitance itself.

According to Biot-Savart and Ampere's laws, the magnetic field lines produced by a straight current-carrying conductor form closed concentric circles centered on the wire. Option A is incorrect because the magnetic field is always perpendicular to the direction of the current, never parallel.

According to Biot-Savart and Ampere's laws, the magnetic field lines produced by a straight current-carrying conductor form closed concentric circles centered on the wire. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Option A is incorrect because the magnetic field is always perpendicular to the direction of the current, never parallel.
• !Options A and B are incorrect because while capacitance relates charge to voltage (C = Q/V), these variables do not change the intrinsic capacitance itself.

Answer each from memory — you'll see instantly whether you're right and why.

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