Introduction

Conductors are materials which allow the electrical current

to pass these materials included the likes of Gold, Copper and Aluminium.

Insulators are the opposite conductors as they don’t let the electrical current

to pass Insulators include the likes of Ceramic, Rubber and Plastic. In between

Conductors and Insulators lays Semiconductors which are usually solid chemical

elements which will allow the electrical current to get pass but under specific

conditions otherwise the current will not get through, which makes

semiconductors very good at controlling the electrical current.

The differences between the electrical behaviour of

conductors and insulators are to do with their electronic structure. In

conductors, the atoms of the material have some loosely bounded electrons which

help the material let the electrical current through. In solid metals atoms

share one or more electrons and some of the electrons are not bound anymore to

a specific atom but they are shared between all atoms which makes them free to

move around. The movement of these electrons conduct the electrical current.

On the other hand, in Insulators all the electrons are

tightly bound to their atoms, none of the electrons are free to move around

which prevents electrical current passing through. Insulators don’t have any

free charged particles which do not let the current flow through.

In semiconductors, most of the electrons are very tight to

their atoms just like insulators but few electrons are free to move around

which can form a weak electric current. Semiconductors can be adjusted with

impurities which can free more or less electrons to move around.

Units used to measure

Electric current ( I )

unit used was ampere ( A )

Inductance ( L ) unit used was henry ( H )

Frequency ( f ) unit used was hertz ( Hz )

Power ( P ) and energy ( E ) units used were watt ( W ) for

Power and joule ( J )

Difference between AC and DC voltages

AC and DC are different types of voltage or current used for

the conduction and transmission of electrical energy. The main difference

between AC and DC is the direction flow of electrical current. DC voltage is

constant and doesn’t change, the flow of the current is in one direction and at

a constant level. On the other hand, AC flows in two directions in a moving

cycle. The flow of the voltage in one direction by going to its peak voltage

and decreasing back to zero at which point the flow reverses directions and

increases back to its peak and goes back to zero to repeat the process.

AC is very efficient at delivering electrical current over

long distances, because the average voltage is zero and the average loss is

also zero. On the other hand, the constant pressure of DC voltage provides high

amounts of power as therefore is used in devices such as electrical motors. The

exceptional power makes it efficient for certain uses, for example its used in

car starter motors.

Can work be negative?

Work is a measurement of energy, and it might seem odd to

see work negative but work can be negative. Considering an objected being

lifted in the upward direction, the force of gravity is acting in the downward

direction. The displacement of the object is in the upward direction and the

angle between the object and the force is 180o the work done by the gravitational force on

the object is negative.

A mass of 1000kg is dropped through a height of 16m in 22s.

To find work done in this question first we need to find the

Force which is F=ma

1000 x 10 = 10,000

acceleration is this case is the gravity pulling the mass towards the

ground

10,000 x 16 = 160,000

Work = 160,000 J

Power developed is

Power = work/time

160,000/22 = 7272.73

Power = 7272.73 W

Household average energy consumption

1 lightbulb over 6

hours, a 60-watts consumption will use 60 x 6 = 0.360 kWh and

60 watt x 6 hours x 60 min x 60 seconds = 60 watt x 21600

secs = 1,296,000 J

10 x 1296000 = 12,960,000 J

1 tv over 4 hours, 100 watts consumption will use 100 x 4 =

0.400 kWh

400 x 14400 = 5,760,000 J

1 washing machine over 3 hours, 1000 watts consumption will use

1000 x 3 = 3 kWh

1000 x 10800 = 10,800,000 J

The total average for 90 days

Light bulbs = 12,960,000 x 90 = 1,166,400,000 J = 324 kWh

TV = 5,760,000 x 90 = 518,400,000 J = 144 kWh

Washing machine = 10,800,000 x 30 = 324,000,000 J = 90 kWh

Average total in Joules = 1,166,400,000 + 518,400,000 +

324,000,000 = 2,008,800,000 J

Average total in kWh = 324 + 144 + 90 = 558 kWh

Cost of electrical bill for 90 days when

its 20p/kWh = 558 x 0.20 = 111.6

The cost of the electrical bill =

£111.60

Practice Section

Introduction to resistors

Resistors are electronic components which have a specific,

never-changing electrical resistance. The resistor’s resistance limits the flow

of electrons through a circuit. Resistors are usually added to circuits where

they complement active components. Commonly resistors are used to limit

current.

The electrical resistance of a resistor is measured in ohms.

The symbol for an ohm is the Greek capital-omega: ?. The definition of 1? is

the resistance between two points where 1 volt 1V of applied potential energy

will push 1 ampere 1A of current.

There are two major categories in resistors and they are

based on whether they are fixed or variable. The fixed resistors are the most

used type of resistor, the values are determined during the design process of

the circuit and the resistor itself should never need to be changed. On the

other hand, variable resistors are resistors which consist of a fixed resistor

element and a slider which taps onto the main resistor element, this gives the

resistor three connections to the component and in this way the resistor is

used as a potential divider if all three connections are used.ConclusionIn conclusion, the practical results were very close to the theoretical

results and no results was outside the ±5% range even though 1 result was

close but it was still in that range which made the practice successful. Before

the practical I expected a few results to be on 220k? and more to be on 219K?

and 221K? but after analysing the results its clear to see that most of the resistor

ended up below 220K? instead of above. The factors which could have affected

the results was possibly taking the result too fast instead of letting it stabilise

a little bit and not moving the resistor around which could have affected my

results and I would take that into consideration when I would repeat this

experiment. References Article title: Conductors

& InsulatorsWebsite title: Learnabout-electronics.orgURL: http://www.learnabout-electronics.org/Resistors/resistors_01.phpDate: 28th December 2017 Article title: Work

and energyWebsite title: Physics.bu.eduURL: http://physics.bu.edu/~duffy/py105/Energy.htmlDate: 30th December 2017 Article title: Differences

between AC and DCWebsite title: Quora.com

URL: https://www.quora.com/What-is-the-difference-between-AC-and-DC-currents