Electrical Services

Question 1

What is ohm law in a DC circuit

Answer 1

Voltage = Current x Resistance V=IR
Current = Voltage ÷ Resitance I=V÷R
Resistance = Voltage ÷ Current R=V÷I

Question 2

What is inductance in an Ac circuit

Answer 2

Inductance is the opposition to current flow in an ac circuit that comes about due to the magnetic field created in a coil.

Question 3

What is capacitance?

Answer 3

Capacitance is the ability of an electrical component to store an electrical charge

Question 4

How do you find the resistance of a circuit

Answer 4

The resistance of a circuit refers to the DC voltage and it is worked out with formula:

R= V÷I 
Resistance = Voltage ÷ Current

Question 5

What is impedance and how do you find it?

Answer 5

Impedance is the overall resistance, opposition to the ac current flow it includes the inductive reactance and capacitance that may cause the opposition and reduce current flow.

Formula:
Z= Vac ÷ Iac
Impedance= Voltage (ac) ÷ Current (ac)

Question 6

What is the formula for inductive reactance?

Answer 6

XL= 2πFL or XL= ωL

Where:
XL= Inductive Reactance
ω = 2πF
L = Inductance measured in Henry’s or milliHenrys

Question 7

What is the formula for inductance of a coil?

Answer 7

L= XL÷2πF

Where
L = inductance
XL = inductive reactance
F = Frequency

Question 8

What is the formula for frequency

Answer 8

f=1÷Tp

Where:
f = frequency
Tp = time period

Question 9

What are the formulas for power?

Answer 9

Power = I²R
= VI
= v²÷R

Question 10

What are the formulas for voltage

Answer 10

Voltage = IR
=P÷I
=√pr

Question 11

What are the formulas for resistance

Answer 11

Ohms= V²÷P
= P÷I²
= V÷I