Which factor does NOT affect the electric power consumed by an electric device?

Question

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The correct answer is Option A: Frequency of the device. Electric power consumed by an electric device is defined as the rate at which electrical energy is dissipated or converted into other forms of energy. It is directly determined by the voltage applied ($V$) and the current passing through the device ($I$), or by the device's resistance ($R$), but it does not depend on the supply frequency ($f$) in standard DC or resistive AC circuits.

Step-by-Step Solution & Concepts:
Electric power consumed by an electric device is defined as the rate at which electrical energy is dissipated or converted into other forms of energy. It is directly determined by the voltage applied ($V$) and the current passing through the device ($I$), or by the device's resistance ($R$), but it does not depend on the supply frequency ($f$) in standard DC or resistive AC circuits.

Working Principle: The electrical power $P$ is calculated using the relation $P = V 	imes I$. By substituting Ohm's law ($V = I 	imes R$), we derive the alternative forms $P = I^{2} 	imes R$ and $P = \frac{V^{2}}{R}$. These formulas establish that power is a function of voltage, current, and resistance. Frequency relates to the oscillation of the AC cycle, which determines the rate of change of direction, but it does not dictate the instantaneous power consumed by a purely resistive load.

Key Formulas: $P = V 	imes I$ — Power in terms of Voltage and Current; $P = I^{2} 	imes R$ — Power in terms of Current and Resistance; $P = \frac{V^{2}}{R}$ — Power in terms of Voltage and Resistance

Key Points: Power ($P$) is measured in Watts (W).; Resistance ($R$) is a physical property of the material/component geometry.; Frequency ($f$) characterizes the AC supply, typically $50\,Hz$ or $60\,Hz$ in power systems.

Applications: Determining wattage ratings for household appliances.; Calculating electrical billing based on energy ($E = P 	imes t$).

Additional Info: Option B (Resistance) directly influences power via $P = I^2R$.. Option C (Voltage) and Option D (Current) are the fundamental variables in $P = VI$.. Frequency is a characteristic of the source (AC), not a factor in the power consumption formula of basic loads.

Answer: A is correct — The electric power consumed by a device is determined by voltage, current, and resistance, whereas frequency describes the oscillation of the AC supply.

Exam Tip: Remember that power is scalar and related to energy transfer; frequency is a temporal parameter and does not alter the resistive power draw $P=I^2R$.

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Option B: Resistance of the device

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Option C: Voltage applied to the device

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Option D: Current passing through the device

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