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Difficulty: EasyElectrical Power

A direct current (DC) automotive lamp connected to a 12 V12\text{ V} power source draws a current of 2 A2\text{ A}. What is the total electrical power consumed by the lamp?

  1. A
    6 W6\text{ W}
  2. B
    14 W14\text{ W}
  3. 24 W24\text{ W}Answer
  4. D
    48 W48\text{ W}

Answer

24 W24\text{ W}
According to Watt's Law, the electrical power (PP) consumed by a circuit load is equal to the voltage (VV) across the component multiplied by the current (II) flowing through it: P=V×IP = V \times I. Substituting the given values yields P=12 V×2 A=24 WP = 12\text{ V} \times 2\text{ A} = 24\text{ W}.

Step-by-Step Solution

1
Identify the given circuit parameters
Voltage (VV) = 12 V12\text{ V}, Current (II) = 2 A2\text{ A}
These are the two electrical quantities necessary to calculate power directly.
2
Select the appropriate electrical power formula (Watt's Law)
P=V×IP = V \times I
When voltage and current are known, power is equal to their product.
3
Substitute the given values into the formula and calculate
P=12 V×2 A=24 WP = 12\text{ V} \times 2\text{ A} = 24\text{ W}
Multiplying electromotive force by current gives total power in watts.

Key Concept

Electrical power in a DC circuit is calculated using Watt's Law (P=V×IP = V \times I), where power in watts is the product of voltage in volts and current in amperes.
Estimated Time:45s
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Topics

Electrical Power

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