The amount of energy utilized to perform certain work in unit time is indicated as power.
Power formula is written as, P = \[\frac{E}{t}\] (power equation)
Also, we can rewrite the power formula as, P = \[\frac{W}{t}\] (power equation)
Here, W = work done
E = Total energy consumed to accomplish work
T = Total time
We can also write the power equation as P = \[\frac{W}{\Delta t}\]
Here, ∆t = Change in time
We use power factor formula in electrical circuits. We can calculate the power with the help of the following formulas.
1st Electrical power formula: P = V × I
2nd electrical power formula = P = I2R
If we combine both first and second electrical power formula, we get:
P = V2R
The above formulas have:
V = Application of a voltage across two terminals
I = Electric current passing through the circuit
R = Resistance
We use a power factor formula to calculate the power in a circuit with active voltage and current within a certain time. We also use them to find the unknown parameters of resistance, voltage, and current. ‘Watt’ is the standard metric unit applied for power.
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The electrical energy formula calculation is pretty easy. It is the total work done (energy) provided by the source of e.m.f. to maintain the current flow in a circuit within a definite time.
Electric energy: E = P × t
= V × I × t
= I2 × R × t
P = V2t / R
The dimensional formula of power is,
[M1 L2 T-3]
Here,
M = Mass
T = Time
L = Length
Power (P) = Work × time-1 = Joule × second-1 …. (1)
We know that
Work (J) = N × m
= M1 L1 T-2 × [L]
Therefore,
The dimensional formula of work = M1 L2 T-2 …. (2)
If we replace equation (2) in equation (1) we get,
Power (P) = Work × time-1
Or, P = [M1 L2 T-2] × [T-1]
= M1 L2 T-3.
This is why the dimensional formula of power is represented as M1 L2 T-3.
The perfect formula that can calculate the average power formula value is:
P\[_{ave}\] = \[\frac{1}{T_{2} - T_{1}}\] \[\int_{T_{1}}^{T{2}}\] V(t)I(t)dt
To calculate the power calculation formula, we have to remember three equations. They are:
P (watts) = V (volts) x I (amps)
P (watts) = I2 (amps) x R (Ω)
P (watts) = V2 (volts) ÷ R (Ω)
This is the power triangle.
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Before the calculation of power consumption formula, you have to make sure what the watt of the device uses per day is. You can multiply the mentioned watt value by the number of hours of its usage.
The result you obtain is watt-hours which is the power consumption of the day.
Power consumption formula = Device Wattage (watts) x Hours Used Per Day
The tabular form of electricity formulas is given hereunder:
Quantity | Formulas | Unit |
Current [I] | I = Q / t Q = Charge t = time taken | Amperes (A) |
Voltage [V] | V = E / Q or V = W / Q E = Energy W = Work done | Volts (V) |
Resistance [R] | R = ρ*l / A ρ = Resistivity, l = length, A = Area or, R = V / I | Ohm (Ω) |
Power [P] | P = VI | Watts (W) |
Conductivity [σ] | sigma = 1 / ρ | Siemens per meter (S/m) |
We all know about energy. Energy is the term that is used to explain the capacity to perform any kind of work. This content is sufficient enough to guide you regarding different formulae associated with power.
Q1. An Electric Lamp has Been on for the Last 4 Hours. The Amount of Current is 0.6 A. Find the Charge.
Ans: Charge Q = I × t
= 0.6 × [4 * 3600]
Q = 8640 C
Q2. Find the Current in a Circuit, if the Voltage is 210 V and the Resistance is 70 Ohms.
Ans: Current I = V / R
= 210 / 70
I = 3A
Q3. What is the Power Used to Produce 400 J Energy within 20 Seconds?
Ans: Power = W / t = 400 J / 20 s = 20 Watts
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