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What is the power rating of a device that draws 1.75 A of current when connected to a 180-V source?
105 W
315 W
225 W
440 W
315 W
The power rating of an electrical device is calculated as the product of the voltage across it and the current flowing through it. Given a voltage (V) of 180┬аV and a current (I) of 1.75┬аA, the power (P) is 180├Ч1.75=315┬аW.
The power rating of an electrical device is calculated as the product of the voltage across it and the current flowing through it. Given a voltage (V) of 180┬аV and a current (I) of 1.75┬аA, the power (P) is 180├Ч1.75=315┬аW.
Think of electrical voltage like water pressure in a pipe and current like the rate of water flow; the total power or work the water can do per second is a combination of both its pressure and how much water is flowing.
Remember P-I-V-E (Power = Current ├Ч Voltage, or simply P=VI).
P=V├ЧI тАФ Electrical power formula
V=I├ЧR тАФ Ohm's law
P=I2├ЧR тАФ Power in terms of current and resistance
According to Joule's law and electrical power relations, electric power represents the rate at which electrical energy is transferred by an electrical circuit. The fundamental formula linking power, voltage, and current is derived from Ohm's law (V=I├ЧR), resulting in P=V├ЧI. Substituting the given values gives P=180┬аV├Ч1.75┬аA=315┬аW (Watts or Joules per second).
Electric power is measured in Watts (W) or Joules per second.
Voltage (V) is measured in Volts (V), representing electrical potential difference.
Current (I) is measured in Amperes (A), representing the rate of charge flow.
The power rating indicates the rate at which the device consumes electrical energy.
Enables accurate calculation of electrical load requirements.
Helps in selecting appropriate fuses and wiring sizes to prevent overloads.
Assumes steady-state DC or RMS AC values without accounting for power factor in complex reactive loads.
Sizing household appliances and electrical circuits.
Determining electricity consumption and energy bills.
1 Watt is equivalent to 1 Joule per second.
Option A (105 W), Option C (225 W), and Option D (440 W) are incorrect because they do not equal the product of 180├Ч1.75.
B is correct тАФ The power rating of a device drawing 1.75 A at 180 V is 315 W.
Always verify units before multiplying; ensure current is in Amperes and voltage in Volts to yield power directly in Watts.
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