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Difficulty: MediumElectrical Power

An electrical heating strip installed in an outdoor surveillance camera enclosure is connected across a 24 V24\text{ V} direct-current (DC) power source and draws an operating current of 750 mA750\text{ mA}. What is the total electrical power consumed by the heating strip?

  1. A
    32 W32\text{ W}
  2. B
    18000 W18{}000\text{ W}
  3. 18 W18\text{ W}Answer
  4. D
    13.5 W13.5\text{ W}

Answer

18 W18\text{ W}
Electrical power is calculated using the formula P=V×IP = V \times I. Converting 750 mA750\text{ mA} to amperes yields 0.75 A0.75\text{ A}. Multiplying the supply voltage (24 V24\text{ V}) by the current (0.75 A0.75\text{ A}) gives 18 W18\text{ W}.

Step-by-Step Solution

1
Convert the current from milliamperes (mA) to base amperes (A)
I=750 mA1000=0.75 AI = \frac{750\text{ mA}}{1000} = 0.75\text{ A}
Standard electrical power equations require current to be expressed in amperes.
2
Apply Watt's Law for electrical power
P=V×IP = V \times I
Electrical power equals the product of voltage and current.
3
Substitute the voltage and current values into the equation to calculate power
P=24 V×0.75 A=18 WP = 24\text{ V} \times 0.75\text{ A} = 18\text{ W}
Multiplying the applied potential by the resulting current yields power in watts.

Key Concept

Calculation of electrical power in a direct-current circuit using Watt's Law (P=V×IP = V \times I) with metric unit conversion.
Estimated Time:1m 0s
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Topics

Electrical Power

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