S Current Electricity

Question 1

Current definition

Answer 1

The flow of electrons in a wire

Question 2

What are substances that allow current to flow through them

Answer 2

Substances that allow current flow through them are called electrical conductors
Example tinfoil

Question 3

What are substances that do not allow current/electricity to flow through them

Answer 3

Substances that do not allow current/ electricity to flow through them are called insulators
Example plastic

Question 4

Lamp symbol

Answer 4

Circle with an x in it

Question 5

Ammeter
Voltmeter
Ohm meter symbols

Answer 5

Circle with an A in it
Circle with a V in it
Circle with the ohm symbol in it

Question 6

Resistor symbol

Answer 6

Empty Rectangle

Question 7

What does an ammeter measure

Answer 7

Unit of current which is known as ampere or amps

Question 8

What does a voltmeter measure

Answer 8

A voltmeter measures voltage or rather known as potential difference

Question 9

What are bulbs in series

Answer 9

When bulbs are connected in series the same current Flows in both bulbs. if one bulb blows the other bulb will go out

Question 10

What are bulbs in parallel

Answer 10

When bulbs are connected in parallel each bulb has an independent pathway for current to flow if one bulb blows the second can stay lit

Question 11

What side of a battery is positive and what side of a battery is negative in a circuit symbol

Answer 11

The Long thin line is positive and the thick short line is negative

Question 12

Why does a light bulb glow

What is resistance

Answer 12

The thin wire or filament in the bulb gets hot when a current flows through it.
the material from which the filament was made of has the tendency to resist movement of electrons
we say that the filament provided a resistance to the current

Question 13

How many types of resistors is there
and what are they
What do they do?

Answer 13

There are two types of resistors fixed resistors and variable resistors
Fixed resistors have one value for resistance they are represented in a circuit diagram by a box.
Variable resistors are usually represented with the box with an arrow Crossing diagonally.
An example of a variable resistor is an LDR (light dependent resistor) or thermistor resistance of the thermistor decreases when it’s heated

Question 14

What are the 4 symbols for resistors

Answer 14

Variable ressitor- rectangle with an arrow threw it

Thermistor- variable resistor with a straight line on the other end of the arrow

Fixed resistor- a rectangle

Light dependant resistor- fixed resistor ina circle with 2 arrows pointing at it

Question 15

What is the relationship between voltage current and resistance

Answer 15

Voltage (V)
——-‐—————————————–
Resistance (ohm) × current(I)

Question 16

What does a resistor do or change

Answer 16

A resistor changes the voltage in the circuit

Question 17

What is Ohm’s law

Answer 17

For metallic conductor at constant temperature the current is proportional to the voltage

Question 18

What is a diode

Answer 18

A diode is a device that allows current to flow through it in One Direction

Question 19

What is a trick to know what way to place the diode in a circuit

Answer 19

Turn the triangle in the dial symbol into a p meaning positive.
The positive end of the battery or cell and the positive side of the diode have to be on the same side/meet.

Question 20

What is a light emitting diode LED

Answer 20

An LED will only allow current to flow in One Direction

Question 21

What is forward and reverse biased

Answer 21

Forward biased means the diode has been placed correctly and reverse bias means it has not

Question 22

What is a light-dependent resistor LDR

Answer 22

Is a type of variable resistor that changes resistance dramatically in response to light

Question 23

What is a thermistor

Answer 23

It is a device made of material that reduces its resistance significantly when the temperature of the device changes
Example temperature sensors, fire alarms, ovens and fridges

Question 24

What is power

Answer 24

Power is the rate at which work is done
     W
P= —
      T
The greater the power of the appliance, the more energy it will convert from one form to another in one second

Question 25

What is the connection with power voltage and current

How do you calculate electrical power

Answer 25

Voltage (V) × current (I)