P2.4 Current Electricity

Question 1

How does a current flow?

Answer 1

When we out a metal wire in a circuit the cell creates a force on the free electrons in one direction. This causes the electrons to flow around the circuit

Question 2

What is the current like in a series circuit?

Answer 2

Same everywhere

Question 3

What component measures current?

Answer 3

Ammeter

Question 4

How do you work out charge

Answer 4

Current X time

Question 5

What do conductors have that mean the current can flow easily

Answer 5

Free electrons

Question 6

Why do lamps light up?

Answer 6

When the current flows through the component the energy transfers to the component. The energy transfers to heat and the lamp gets so hot that it glows and some energy is transferred to light energy.

Question 7

What measures voltage? What is voltage exactly?

Answer 7

Voltmeter
It compares the energy carried by the current leaving it. The change in current is due to electrical energy being transferred to other forms in the components

Question 8

What does the energy transferred in a component depend on?

Answer 8

The potential difference

The charge that has flowed through the component

Question 9

How do you work out the energy transformed?

Answer 9

Voltage X charge

Question 10

What’s charge measured in?

Answer 10

Coulombs (C)

Question 11

What is the current like in a parallel circuit?

Answer 11

The current is shared between the branches

Question 12

How are voltmeters connected in a circuit?

Answer 12

In parallel to a component

Question 13

What is voltage like in a series circuit?

Answer 13

It’s shared between components

Question 14

What’s voltage like in a parallel circuit?

Answer 14

Same in every branch

Question 15

Series circuit Parallel circuit

Current (1) (2)

Voltage (3) (4)

Fill in table

Answer 15

1. Same
2. Shared
3. Shared
4. Same

Question 16

Why are lighting circuits in your home in parallel circuits?

Answer 16

Bulbs are bright - voltage is the same

If one breaks the others still light up

Question 17

What things affect resistance?

Answer 17

Number of components
Type of metal
Cross-sectional area of the wire

Question 18

What’s resistance measured in?

Answer 18

Ohms

can’t show you symbol :(

Question 19

What’s the symbol for a fixed resistor in a circuit?

Answer 19

____
-| |-
—–
Basically a rectangle

Question 20

What’s the total resistance in a series circuit?

Answer 20

The sum of all the individual resistances

Question 21

What’s the relationship between voltage and current?

Answer 21

As voltage increases, the current increases but not as quickly

Question 22

How do you calculate resistance?

Answer 22

Voltage / current

Question 23

What’s the relationship between length of wire and resistance?

Answer 23

As the length of wire increases so does the resistance. The thinner the wire the bigger the resistance

Question 24

What’s a diode?

Answer 24

Only lets current go in one direction - very high resistance in the other direction

Question 25

look up graphs for bulb, resistor and diode - make sure you know them
(18th July 2016)

Answer 25

👋🏽👋🏽👋🏽👋🏽👋🏽👋🏽👋🏽👋🏽👋🏽😽
:)
🤗👋🏽👍🏽

Question 26

What’s the circuit symbols for LDR and a thermistor?

Answer 26

Look them up :,)

Question 27

How does resistance in a thermistor change with temperature

Answer 27

As temperature increases, resistance decreases

Question 28

How does the resistance of an LDR change with light intensity?

Answer 28

As lamp gets further away from the LDR the resistance increases

Question 29

How do you work out charge?

Answer 29

Current X time

Question 30

What’s the circuit symbol for a fuse?

Answer 30

A rectangle with a line through it

Question 31

What’s the circuit symbol for a variable resistor

Answer 31

A rectangle with an arrow in it pointing north east