Voltage drop across a resistor in a circuit can be calculated using Ohm's law.

• A. It cannot be calculated
• B. Only in DC circuits
• C. Only for capacitors
• D. Voltage drop across a resistor can be calculated using Ohm's law

Answer: (D)

The main idea here is that Ohm's law directly links voltage, current, and resistance for a resistor: V = I × R. Whatever current flows through a resistor and the value of its resistance, the voltage drop across the resistor is simply the product of those two. This holds whether the circuit is DC or AC, as long as the resistor behaves ideally (constant resistance). In DC, you get a steady drop; in AC, the instantaneous relationship is v(t) = i(t) × R, and the RMS magnitudes satisfy Vrms = Irms × R because the voltage and current remain in phase for a resistor.

So the voltage drop across a resistor can be calculated using Ohm's law. For example, if a 10 Ω resistor has 0.5 A flowing through it, the voltage drop is 5 V.

The other statements aren’t correct because Ohm’s law applies to resistors in both DC and AC contexts (not limited to DC), and it’s specific to resistors (not only capacitors).