KEY FORMULAS FOR CITY & GUILDS 2365 UNIT 302 EXAM LATEST VERSION |NEW AND REVISED

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KEY FORMULAS FOR CITY & GUILDS 2365
UNIT 302 EXAM LATEST 2025-2026 VERSION
|NEW AND REVISED

Ohm's Law - ANSWER- V=I×R (Voltage = Current × Resistance)


Power formulae - ANSWER- P=V×I (Power = Voltage × Current)


Energy consumption - ANSWER- E=P×t (Energy in watt-hours or
kilowatt-hours if P is in kW and t in hours)


Resistances in series - ANSWER- RT=R1+R2+R3+⋯ (Total resistance
= sum of individual resistances)


Resistances in parallel - ANSWER- RT1=R11+R21+R31+⋯ (Total
resistance = sum of inverses of individual resistances)


Frequency - ANSWER- f=T1 (Frequency = time period)


Inductive reactance - ANSWER- XL=2πfL (Inductive reactance = 2π ×
frequency × inductance)


Capacitive reactance - ANSWER- XC=2πfC1 (Capacitive reactance =
2π × frequency × capacitance)

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Impedance in series (R-L-C) - ANSWER- Z=R2+(XL−XC)2
(Impedance = square root of sum of squares of resistance and reactance)


Power factor (pf) - ANSWER- pf=cosϕ (Power factor = ratio of true
power to apparent power)


Apparent power - ANSWER- S=V×I (VA) (Apparent power = Voltage
× Current)


True power - ANSWER- P=V×I×cosϕ (Watts) (True power = Voltage ×
Current × Power factor)


Reactive power - ANSWER- Q=V×I×sinϕ (VAr) (Reactive power =
Voltage × Current × sine of phase angle)


Three phase power (balanced load) - ANSWER- P=3×VL×IL×cosϕ
(Power = 3 × Line voltage × Line current × Power factor)


Mechanical power (rotational) - ANSWER- P=2πNT/60 (Power = 2π ×
rpm × torque / 60)


Force - ANSWER- F=m×a (Force = mass × acceleration)


Work - ANSWER- W=F×d (Work = Force × distance)