Ele Scin

Question 1

Total power

Answer 1

P = v I
Power = volts x amps (Dc only)

Question 2

Power in series
No Dc

Answer 2

2
P = I X R
Power = volts squared x rsistence

Question 3

Ohm’s law

Answer 3

Voltage equals = resistance x current

Question 4

What does I stand for?

Answer 4

Amperage/current

Question 5

What does P stand for in an equation?

Answer 5

Watts /power

Question 6

What does V stand for an equation?

Answer 6

Volts/ voltage

Question 7

What does R stand for in an equation?

Answer 7

Resistance/ oems

Question 8

Which way does electricity flow in a diagram?

Answer 8

From positive to negative

Question 9

What are the three possible effects of an electric current?

Answer 9

Thermal
Chemical
Magnetic

Question 10

Kirchoffs current law

Answer 10

The sum of current arriving at a point must be equal to the sum of current leaving that point

(parallel circuit only)

Question 11

Kirchoff’s voltage law

Answer 11

The sum of the voltage around a current is equal to 0 or (the supply voltage)

In other words the total voltage drop has to equal the supply voltage

Question 12

Power equation with resistance in parallel

Answer 12

Power = voltage squared over resistance
2
P = v / R

Question 13

What is the resistivty of copper

Answer 13

-9
17.2 x 10 Ohm meter

Question 14

What is the resistivity of Aluminium

Answer 14

-9
26.5 x 10 ohm meter

Question 15

How to calculate flux denstity

Answer 15

2
Fux (Weber) divided by area (cm ) = fux density in Tesla (t)

Question 16

Resistance in cross-sectional area is

Answer 16

Inversely proportional to its area

Question 17

How to calculate Resistance
With resistivity
Length and cross-sectional area

Answer 17

Resistance= resistance( ohms) x length(m) divided by cross-sectional area/ csa in (m squared )

Question 18

How to calculate magnetic flux density

Answer 18

Magnetic flux ( in Tesla T / webers per square meter / wb/m squared) divided by cross-sectional area of flux ( m square)

B=\o/A

Question 19

How to calculate EMF
Electromagnetic force

Answer 19

e=B x l x v
/
EMS in (v) = magnetic flux in (t) x length of conductor in (m) x velocity of conductor(m/s)

Induced EMF in volts
Magnetic flux in Tesla
Length of conductor in metre
Velocity of conductors in metre per second

Question 20

In what direction does magnetism flow?

Answer 20

North to south

Question 21

What is the force that “pushes” electrons arectrocal circuit

Answer 21

E m f
Electron motive force

Question 22

What are the components of an electromagnet?

Answer 22

A solenoid ( coiled wire) and a metal core
Normally steal

Question 23

Which electrical component is used in modern dimmer switches?

Answer 23

Triac

Question 24

A preset temperature of an immersion heater is maintained by

Answer 24

A thermostat

Question 25

The voltage of an alternator is shown in

Answer 25

Sinusidal wavefrom

Question 26

What is the definition of one ampere

Answer 26

1 ampere = 1 coulomb per Second

Question 27

What type of meter uses a small voltage and current to determine its value?

Answer 27

Ohmmeter

Question 28

What is the SI unit for capacitance

Answer 28

Farad

Question 29

What is the formula for energy?

Answer 29

P = w/t Power equals watts divided by time?

Question 30

How do you determine voltage in a circuit?

Answer 30

Watts / amperes

Question 31

What are the three types of resistors?

Answer 31

Fixed resistor , variable resistor Light dependent resistor

Question 32

What is the equation for effort? In leathers

Answer 32

Load times load to Velcro distance Divided by effort to Fulcrum distance

Question 34

The meter used in an electrical installation for recording the energy used is called

Answer 34

a kilowatt hour meter

Question 35

The steady flow of a large amount of electrons is

Answer 35

Current

Question 36

The frequency of an alternating current 1/1 (AC) is the...

Answer 36

Number of cycles per second

Question 37

What is the SI unit for mass? As well as it’s quantitive symbol

Answer 37

Kg and m

Question 38

The St unit of weight is the...

Answer 38

Newtons

Question 40

An electromagnetic device which allows 1/1 a high current circuit to be controlled by a low current switch is known as

Answer 40

A Relay

Question 41

What must you times Celsius by to get to Kelvin?

Answer 41

-273.15