Circuits

Question 1

What is the energy change in a washing machine?

Answer 1

In a washing machine, the energy change is

electrical energy to heat and kinetic energy.

Question 2

What is the name of this component?

Answer 2

Variable resistor

Question 3

How many pencils are there?

Answer 3

Question 4

What unit is resistance measured in?

Answer 4

Resistance is measured in ohms.

Question 5

What is the name of this component?

Answer 5

Lamp

Question 6

What is the name of this component?

Answer 6

Loudspeaker

Question 7

What unit is voltage measured in?

Answer 7

Voltage is measured in volts (V).

Question 8

Describe how to use an ammeter to measure the current in a component.

Answer 8

An ammeter must be connected in series with a component.

Question 9

What does the prefix k stand for?

Answer 9

k stands for kilo

kilo = x 10³

Question 10

Which quantity is represented by the symbol I?

Answer 10

I = current

Question 11

Why does an L.E.D. always have a resistor connected in series with it?

Answer 11

An L.E.D. always has a resistor connected in series with it to protect the L.E.D.

The resistor will limit the current in the L.E.D.

Question 12

Which quantity is represented by the symbol R?

Answer 12

R = resistance

Question 13

What is the name of this component?

Answer 13

Fuse

Question 14

What is the name of this component?

Answer 14

L.E.D. (light-emitting diode)

Question 15

Which quantity is represented by the symbol V, in the equation shown ?

Answer 15

voltage

(or potential difference)

Question 16

Round off this number to 3 significant figures.

1,526.33

Answer 16

1,526.33 rounded off to 3 significant figures is

1,530

(the ‘2’ has been rounded up to 3)

Question 17

Round off this number to 3 significant figures.

3.14159

Answer 17

3.14159 rounded off to 3 significant figures is

3.14

Question 18

What unit is current measured in?

Answer 18

Current is measured in amperes (A).

Question 19

What is the name of this component?

Answer 19

L.D.R. (light-dependent resistor)

Question 20

What is the name of this component?

Answer 20

Cell

Question 21

Name as many different types of energy as possible.

Answer 21

Kinetic, potential, electrical, chemical, light, heat, sound, nuclear

Question 22

What is the name of this component?

Answer 22

Motor

Question 23

How could the resistance of a component be found from this graph?

Answer 23

The resistance could be found by

(a) calculating the gradient of the graph
(b) choosing a point on the graph and calculating voltage / current

Question 24

What does the prefix m stand for?

Answer 24

m stands for milli

milli = x 10^-3

Question 25

What is the definition of current?

Answer 25

Current is how much electrical charge flows (past a point) in one second.

Question 26

What does a.c. stand for, and what does it mean?

Answer 26

a.c. stands for alternating current, which means the current changes direction every fraction of a second.

Question 27

How many types of electric charge are there, and what are their names?

Answer 27

There are two types of electric charge - positive and negative

Question 28

Describe how to use a voltmeter to measure the voltage across a component.

Answer 28

A voltmeter must be connected in parallel with a component.

Question 29

What is the name of this component?

Answer 29

Resistor