P4

Question 1

To have charge flow, the circuit must…

Answer 1

• be close (no open switches)
• there must be a source of potential difference (battery/cell)

Question 2

What is current

Answer 2

Flow of electrical charge

Question 3

Equation for charge flow

Answer 3

Q=IT
q= charge flow (coulombs C)
I= current (amps A)
T= time (seconds)

Question 4

What does the greater resistance result in?

Answer 4

The smaller current for a given potential difference across the component

Question 5

Equation linking potential difference, current and resistance

Answer 5

V=IR
V = potential difference (volts)
I= current in amps
R= resistance

Question 6

What does it mean when the graph is linear

Answer 6

The resistance is constant, an ohmic conductor, current is directly proportional to the potential difference

Question 7

What does it mean when the graph is non-linear

Answer 7

The resistance of componants such as lamps, diodes, thermistors, and LDRs is not constant and it changes wiht the cyrrent through the componant

Question 8

How does the resistance change with current

Answer 8

As the current increases, electrons has more energy.
When the electrons flow through a resistor, they collide with the atoms in the resistor
This transfers energy to the atoms, causing them to vibrate more
This makes it more difficult for electrons to flow throuh a resistor
So as resistance increases and the current decreases

Question 9

How does resistance change with temperature

Answer 9

In hotter temperatures the resistance is lower

Question 10

How does the resistance change with length

Answer 10

The greater the length, the more resistance and the lower current. This is because the electrons make their way through more resistor atoms, so its harder than using a shorter wire

Question 11

How does the resistance change with light

Answer 11

The greater the intensity of the light, the lower the resistance. So the resistance is greater when its dark

Question 12

How does resistance change with voltage

Answer 12

Diode allows current to flow freely in one direction. In the opposite direction, it has a very high resistance so no current can flow through

Question 13

What does a circuit need to have to be a series circuit

Answer 13

• close circuit
• current only flows a single path
• the current is the same everywhere

Question 14

Equation for total resistant in a series circuit

Answer 14

Total resistance = R1 + R2 + …

Question 15

What does the circuit need to have for it to be a parrellel circuit

Answer 15

• branched circuit
• current splits into multiple paths
• total current into multiple paths
• the potential difference is the same across each branch

Question 16

What is potential difference

Answer 16

Measure of energy transfered between 2 points in a circuit