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WorksheetsSome Electrical Formulas Quiz
Total questions: 20
Worksheet time: 10mins
According to Ohm's Law, which of the following is the correct relationship between Voltage (V), Current (I), and Resistance (R)?
V = I + R
V = I / R
V = IR
V = I - R
What is the formula for power (P) in an electrical circuit?
P = IV
P = I/R
P = I + V
P = I²R
Which formula represents the force (F) on a conductor carrying current (I) in a magnetic field (B) with length (L)?
F = BIL
F = B/I
F = BL/I
F = B + I + L
How is the efficiency (η) of a device calculated?
η = (Output/Input) × 100%
η = (Input/Output) × 100%
η = Output - Input
η = Input - Output
What is the relationship between Joules (E) and Watts (P) over time (T)?
E = P × T
E = P / T
E = P + T
E = P - T
What is the formula for the RMS (Root Mean Square) value?
RMS Value = 0.7071
RMS Value = 1.4142
RMS Value = 2
RMS Value = 0.5
Which formula is this?
Resistance
Resistivity
Joule's Law
Rho's Law
Which formula is this?
Motors
Generators
Transformers
Earth fault loop impedance
What is the periodic time of a frequency of 25Hz?
0.4 seconds
40 milli seconds
2.5 seconds
If the periodic time is 0.01 seconds, what is the frequency?
How much charge would there be if 4 amps flowed for 20 seconds?
24 Coulombs
5 Coulombs
If 30 Coulombs of charge passes a point in 10 seconds, what's the current?
If the line voltage is 440 volts in a star transformer, what's the phase voltage?
440 volts
762 volts
244 volts
254 volts
If the line current is 10 amps in a star transformer, what's the phase current?
10 amps
17.3 amps
5.8 amps
20 amps
Maximum permitted volt drop for lighting circuits?
Maximum permitted voltage drop for power circuits?
3%
5%
7%
10%
On a 230V system, how much current will a 2kW load draw?
If my earth fault loop impedance is 0.1 ohms, what would the prospective fault current be on a 230V system?
What number do you multiply by to get from mm² to m²? (Think area in a resistivity question)
10³
10⁶
10⁻³
10⁻⁶
If you get a motor question, do you use Flemings left hand or right hand rule?
Left
Right
