chapter 13 : electrical systems

Question 1

What are the main components of an electrical system?

Answer 1

• cell (battery)
• electric charge
• connecting wires
• electrical devices eg bulb

Question 2

what is the rate at which electric charge flows?

Answer 2

electric current, I

Question 3

the greater the flow of electric charge per unit time,

Answer 3

the larger the current

Question 4

what is an ammeter for?

Answer 4

to measure the current flowing through an electric circuit

Question 4

how is an ammeter arranged to measure the current flowing?

Answer 4

the ammeter is connected in series within a circuit

Question 4

what is the SI unit of electric current?

Answer 4

ampere (A)

Question 5

the negative terminal of the ammeter is connected to?

Answer 5

the negative side of the cell

Question 5

what is the use of a voltmeter?

Answer 5

to measure the potential difference between two points in an electric circuit

Question 6

what is the SI unit for potential difference?

Answer 6

volt (V)

Question 6

how is a voltmeter arranged to measure the potential difference across an electrical component?

Answer 6

a voltmeter is connected in parallel to the electrical component

Question 7

what is electrical resistance, R?

Answer 7

a measure of how much the component opposes the flow of electric current

Question 8

the negative terminal of the voltmeter is connected to?

Answer 8

the negative end of the cell

Question 9

electrical conductors have very low resistance to current,

Answer 9

electrical insulators have very high resistance to current, too high until current cannot flow through them.

Question 10

what are resistors?

Answer 10

electrical components that reduce the flow of current in a circuit.

Question 10

what is the SI unit of electrical resistance?

Answer 10

ohm

Question 11

what happens when a resistor is added to a circuit?

Answer 11

it will be more difficult for electric charge to flow in the circuit

Question 12

what are the two types of resistors?

Answer 12

• fixed resistor, which has fixed, non-adjustable electrical resistance
• variable resistor, which has a range of electrical resistance that can be adjusted

Question 13

variable resistors are used in households?

Answer 13

to control the current in a circuit. eg dimmers

Question 13

what is a rheostat?

Answer 13

a type of variable resistor that can be adjusted to control the amount of current flowing through a circuit.

Question 14

what is the SI unit of power

Answer 14

watt (W)

Question 15

what is fuse?

Answer 15

an electrical component that is used to protect the electrical appliance from excess current

Question 16

when multiple plugs are inserted into the same socket,

Answer 16

a very large amount of current may be drawn from the power supply, which can result in excessive heat, causing wires to melt and even cause a fire

Question 17

how to increase electromagnetism?

Answer 17

• more no. of coils
• more no. of cells