P2 - Electricity

Question 1

What is electric current and measurement? What is current and measurement?

Answer 1

Flow of electric charge, ampere. Flow of charge, Amps

Question 2

Describe current in a series circuit

Answer 2

Same everywhere

Question 3

Describe the flow of current and units

Answer 3

Current flows in the oppositely charged direction,

Question 4

What is potential difference, what does it tell us and what is its measurement?

Answer 4

Driving force that pushes charge/current around, tells us how much energy electrons carry, measured in Volts

Question 5

What is resistance and its units

Answer 5

Resistance is anything that slows the flow down. Ohms

Question 6

What does the current flowing through a component depend on?

Answer 6

Depends on the p.d across it and the resistance of the component

Question 7

What does the size of the current show?

Answer 7

Size of the current is the rate of flow of charge

Question 8

Describe the relation between the resistance across a component and the current that flows?

Answer 8

The greater the resistance across a component, the smaller the current that flows

Question 9

What is the charge flow equation and what do they mean and units

Answer 9

Q = It
Charge Flow = Current x Time
C = A x S

Question 10

Why do we do repeats?

Answer 10

To calculate mean to reduce errors and identify anomalies.

Question 11

How do we make an experiment valid?

Answer 11

Controlling other variables, make it reproducible with accurate measurements

Question 12

How do we make an experiment reproducible?

Answer 12

Other groups repeat it and get the same results using same method

Question 13

Why do we turn it on and off before each reading?

Answer 13

To control temp, temp affects resistance

Question 14

Describe the wire length experiment

Answer 14

Attach c.c to wire at 0 cm on ruler
Attach second c.c to the wire 10 cm away from first clip, write down length of wire between clips
Attack ammeter in series to the wire to record current, voltmeter in parallel to wire
Close switch then record current through wire and pd across it
Open switch, move cc another 10 cm, close switch, record new length, current and pd
Repeat for a number of different lengths
Use measurement of current and pd to calculate r because p = ir

Question 15

Why do we open and close switch between wire experiment

Answer 15

To control temperature and temperature affects resistance

Question 16

Which type of wire will be the most suitable for this experiment and give the best results

Answer 16

Thin wire

Question 17

What are ohmic conductors and give examples

Answer 17

Components where current is directly proportional to pd, so r does not increase when I increases wires and FIXED resistors

Question 18

To construct an IV characteristic for an ohmic conductor, what two things would you need to measure and how are they measured?

Answer 18

Current - in series to component with ammeter
Potential Difference - in parallel to component with voltmeter

Question 19

What is the purpose of a variable resistor?

Answer 19

To change resistance/current through the component

Question 20

What happens when the battery direction is swapped and why

Answer 20

Reverse direction of current, take negative reading