The formula for electric power is P = VI, where P is power in watts, V is voltage in volts, and I is current in amperes.
How is power related to energy consumed?
Power is the rate at which energy is consumed. Energy consumed is power multiplied by time (E = P × t).
What are the units of power?
The units of power are watts (W), kilowatts (kW), and megawatts (MW).
What is an electric power circuit example?
An example is a simple circuit with a battery and a light bulb. Power in this circuit is calculated using voltage from the battery and current through the bulb.
What happens to power if only the voltage increases?
If voltage increases while current remains constant, power also increases according to the formula P = VI.
How can power be calculated using resistance?
Power can be calculated using resistance with the formula P = I²R, where I is current and R is resistance.
What is the relationship between power and efficiency?
Efficiency is the ratio of useful power output to total power input, often expressed as a percentage.
How is power different in AC and DC circuits?
In AC circuits, power can vary with time. In DC circuits, power is constant as current and voltage remain unchanged.
What is the role of transformers in power calculation?
Transformers change voltage levels, affecting the power distribution without changing frequency, which influences current and efficiency.
Why is understanding electric power important?
Understanding electric power is crucial for designing and managing circuits, ensuring safety and efficiency in electrical systems.
How does the power factor affect AC power calculations?
Power factor, ranging from 0 to 1, measures efficiency; low values indicate poor efficiency, appearing as phase differences in power calculations.
What instruments measure electric power?
Instruments like wattmeters and multimeters measure electric power by assessing voltage and current.
What is the significance of kilowatt-hour (kWh)?
Kilowatt-hour is a unit of energy representing the power consumption over time, typically used for billing electricity usage.
How does resistance affect power in a circuit?
Higher resistance reduces current for a given voltage, lowering power according to P = V²/R.
What safety factors must be considered in power calculations?
Safety factors include maximum voltage levels, current capacities of wires, and circuit breaker settings to prevent overload.