4.2.1.2 Electrical and Charge Current

Question 1

For electrical charge to flow through a closed circuit what must the circuit include?

Answer 1

for electrical charge to flow through a closed circuit the circuit must include a source of potential difference

Question 2

What is charge measured in?

Answer 2

Coulombs (C)

Question 3

The Bakery Model (what everything represents)

Answer 3

1. The bakery is like the battery (cell) in the circuit
2. The vans are like the charge, 1 van represents 1C of charge
3. The bread the vans are carrying is like the energy carried by the charge in the wire
4. The supermarket is like the bulb. Here, the bread is passed onto the customers just like the energy carried by the charge is transferred to thermal energy and light energy in the bulb
5. The empt vans return to the bakery for more bread. This is the same as charges going back to the cell for more energy
6. If the bakery manager speeds up the vans leaving the bakery, bread arrives quicker at the supermarket. This is like charges arriving more quickly at the bulb in the circuit
7. If the bakery manager loads more bread onto each van, then more bread is delivered to the supermarket in a certain time. This is like more energy being delivered to the bulb in a certain time in the circuit.

• The chain of moving vans is like the flow of charge. In a circuit we call this electrical current

Question 4

What is a Coulomb made up of?

Answer 4

many electrons

Question 5

What does current measure?

Answer 5

Current measures the rate of flow of charge

Question 6

Unit for current:

Answer 6

current is measured in amperes (A)

Question 7

How is current measured?

Answer 7

current is measured with an ammeter connected in series

Question 8

What is the value of current in a single closed loop?

Answer 8

has the same value

Question 9

What is one amp equivalent to?

Answer 9

one amp is equivalent to one Coulomb of charge passing a point each second

Question 10

What is an electrical field?

Answer 10

• anything with a charge has an electric field
• an electric field is created around any electrically charged object
• an electric field is a region where a force acts on a charged particle

Question 11

Formula to calculate current:

Answer 11

Question 12

What does the chain of moving vans in the Bakery Model represent?

Answer 12

• The chain of moving vans is like the flow of charge
• In a circuit we call this electrical current
• number of vans passing a certain point each second represents current

Question 13

What is one van equal to?

Answer 13

van = charge

1 van represents 1C of charge

Question 14

When does current in a circuit change?

Answer 14

current changes when the circuit changes