Electricity and Magnetism

Question 1

define and give examples of static electricity

Answer 1

static electricity is the build-up of electrons in one place e.g. lightning, rubbing a balloon against your hair

Question 2

define current electricity

Answer 2

electric current is the flow of electrons

Question 3

what and why is the relation of the flow of conventional current and the flow of electrons

Answer 3

opposite

conventional current goes positive to negative and electrons go negative to positive

Question 4

distinguish between an electrical conductor and an insulator

Answer 4

*Components that allow electricity to flow through easily are good conductors
*Components that make it hard for current to flow are good insulators

Question 5

compare a series circuit with a parallel circuit

Answer 5

*in a series circuit, there is only one path for the electricity to travel as it has no branches or junctions and components are one after the other. Every component has to work or else no components will work
*in a parallel circuit, there are two or more individual circuits connected to the same power supply, each branch takes its own supply of current from the cell/battery

Question 6

define voltage

Answer 6

The potential difference in a circuit

Question 7

what unit do you measure voltage in

Answer 7

volts

Question 8

define current

Answer 8

the flow of electrical charge in a circuit

Question 9

what unit do you measure current in

Answer 9

amps

Question 10

how do you correctly set up and record the current and voltage in a parallel circuit

Answer 10

*ammeter - at the back of all the branches and before the current goes into any branch
*voltmeter - before and after each component

Question 11

how do you correctly set up and record the current and voltage in a series circuit

Answer 11

*ammeter - goes anywhere
*voltmeter - the wires go before and after every component

Question 12

define resistance

Answer 12

how much opposition there is to a current

Question 13

what units do you measure resistance in

Answer 13

ohms (Ω)

Question 14

what is the relation of resistance between conductors and insulators and why

Answer 14

*conductors have low
*insulators have high

*conductors allow the electricity to flow through it & insulators don’t

Question 15

what is an LDR

Answer 15

*a component with a resistance that depends on light intensity - used to detect light levels

Question 16

how does an LDR work in a circuit in both low and strong light

Answer 16

*they have low resistance in strong light
*they have high resistance in the dark

Question 17

what and why takes the easiest route

Answer 17

charge as it wants to get round the circuit as quickly as possible and will do it in the quickest way possible

Question 18

what does a diode do

Answer 18

*only allows electricity to pass through it in one direction

Question 19

explain what an LED is and how it works

Answer 19

*a diode that emits light when a small current flows through it
*it only allows light to flow through it in one direction

Question 20

what is the role of switches

Answer 20

to control when current goes through a circuit

Question 21

switch

Answer 21

open - two lines leading up to two different dots and a line from one of the dot is going above the other dot
closed - two lines leading up to two different dots and there is a line connecting them together

Question 22

cell

Answer 22

two lines leading up to two different lines and one line is bigger than the other

Question 23

battery

Answer 23

two cells and a dotted line going from a short line to a long line

Question 24

diode

Answer 24

a side on triangle with a line going through it inside a circle

Question 25

resistor

Answer 25

a blank box with a line leading up to it on both sides

Question 26

variable resistor

Answer 26

a blank box with a line leading up to it on both sides with an arrow going from bottom left to top right

Question 27

LED

Answer 27

a side on triangle with a line going through it inside a circle with two arrows pointing to the top right on the top right of it

Question 28

bulb/lamp

Answer 28

a circle with an X in the middle with a line leading up to it from both sides

Question 29

fuse

Answer 29

a box with a line going through it

Question 30

voltmeter

Answer 30

a circle with a V in the middle of it and lines leading up to it from both sides

Question 31

ammeter

Answer 31

a circle with a A in the middle of it and lines leading up to it from both sides

Question 32

thermistor

Answer 32

a blank box with an a line the goes from top right to bottom left and at the bottom there is a line going left

Question 33

LDR

Answer 33

a circle with a box in the middle and arrows in the top left pointing bottom right with lines leading up to it from both sides

Question 34

motor

Answer 34

a circle with the letter M in the middle and lines leading up to it from both sides

Question 35

buzzer

Answer 35

two 90 degree angles that lead up to a semi-circle with the flat side facing up