Science 103 Outcomes 1-6

Question 1

What is the SI Unit for Volume?

Answer 1

Cubic metres

Question 2

What is the SI Unit for density?

Answer 2

kilogram per metre

Question 3

What is the SI Unit for velocity?

Answer 3

metres/second

Question 4

What is the SI Unit for resistance?

Answer 4

Ohms

Question 5

What is the SI Unit for resistivity?

Answer 5

Ohm metre

Question 6

What is the symbol for resistivity ?

Answer 6

p (weird p) Rho

Question 7

What is the SI Unit for impedance ?

Answer 7

Ohms

Question 8

What is the SI Unit for inductance ?

Answer 8

Henry

Question 9

What is the SI Unit for inductive reactance? (xL)

Answer 9

ohms

Question 10

What is the SI Unit for capacitance?

Answer 10

Farad

Question 11

What is the SI Unit for capacitive reactance? ( Xc)

Answer 11

Ohms

Question 12

What is the SI Unit for Reactive power?

Answer 12

Volt ampere reactive VAR

Question 13

What is the SI unit for apparent power?

Answer 13

Volt amps VA

Question 14

What do I need to remember about the current in a mixed series + parallel circuit ?

Answer 14

when it gets to the parallel part it will divide up equally to each resistor

Question 15

Ohms law formula

Answer 15

V= I x R

Question 16

Formula for resistance in a parallel circuit

Answer 16

1/RT = 1/R1 + 1/R2 + 1/R3

Question 17

Formula for resistance in a series circuit

Answer 17

RT = R1 + R2 + R3

Question 18

Name the two power formulas

Answer 18

P = V x I
or
P = I^2 x R

Question 19

Formula for efficiency

Answer 19

Weird n = OUTPUT/INPUT

Question 20

Formula to find input using efficiency and output

Answer 20

INPUT = OUTPUT/efficiency

Question 21

What is voltage drop?

Answer 21

The decrease of electrical potential along the path of a flowing current in a circuit (due to resistance)

Question 22

In a circuit the sum of the volt drops should add up to…

Answer 22

the total voltage

Question 23

What are the three basic rules of magnetism?

Answer 23

• lines of flux cannot cross
• lines of flux flow from north to south
• like poles repel

Question 24

What does a cross represent?

Answer 24

Current flowing away

Question 25

What does a little dot represent?

Answer 25

Current flowing towards

Question 26

How do you calculate the flux density?

Answer 26

B= flux density x area

Question 27

What is flux density (as in number of lines) measured in?

Answer 27

Webers

Question 28

What is flux density measured in? normal

Answer 28

Tesla

Question 29

How do you calculate the frequency in AC generation?

Answer 29

f = N(speed in revs per sec) x no of pole pairs

Question 30

Explain the left hand rule

Answer 30

Thumb - direction of conductor first finger - field (N on your palm) Second finger - current

Question 31

How do you calculate mechanical force on the conductor?

Answer 31

F = B(flux density) x I (current) x length

Question 32

What is the purpose of a thyristor in the alarm circuit?

Answer 32

It operates the sounder

Question 33

What is the purpose of the capacitor in a telephone socket?

Answer 33

It forms part of the ringer circuit

Question 34

What is the purpose of the bridge rectifier in the motor control circuit?

Answer 34

It converts AC to DC

Question 35

In the thermostat what is the purpose of the thermistor?

Answer 35

It detects the temperature in order to turn appliances on and off using resistance

Question 36

In the dimmer switch, what is the purpose of the DIAC?

Answer 36

To trigger the DIAC

Question 37

What is a thermistor?

Answer 37

A type of resistor that varies with temperature

Question 38

What is a diode?

Answer 38

Allows current to pass in only one direction

Question 39

What is a thermistor?

Answer 39

A device that conducts when its gate receives a current trigger

Question 40

Which device converts AC to DC?

Answer 40

A rectifier

Question 41

What is impedance measured in?

Answer 41

Ohms

Question 42

What effect is electroplating?

Answer 42

Chemical

Question 43

What is the SI unit for resistivity?

Answer 43

(littlehorseshoesymbol)m

Question 44

What is a crowbar an example of?

Answer 44

A class I lever

Question 45

What is the effect if a motor is connected to a cable with an extremely high resistance?

Answer 45

There will not be enough voltage to operate the motor

Question 46

What is magnetic flux density?

Answer 46

the amount of flux in a given area

Question 47

How do we calculate the induced EMF within a conductor?

Answer 47

E =v x B x i