Chapter 10 heat and electricity

Question 1

Electrical current

Answer 1

a path for electrons to follow, consisting of a power supply, one or more loads, and conductors joining the power supply and loads

Question 2

Electrical charge

Answer 2

physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge can be positive or negative.

Question 3

Nucleus

Answer 3

central part of an atom, made up of protons and neutrons; roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.

Question 4

Electrons

Answer 4

negatively charged, very light particles in an atom. Electrons move around the nucleus of the atom.

Question 5

Negative electric charge

Answer 5

the charge on an atom or object with more electrons than protons

Question 6

Protons

Answer 6

positively charged particles found in the nucleus of an atom

Question 7

Positive electric charge

Answer 7

the charge on an atom or object with fewer electrons than protons

Question 8

Neutrons

Answer 8

particles with no electrical charge that are found in the nucleus of an atom

Question 9

Positively charged

Answer 9

having more protons than electrons (more positive charges than negative charges)

Question 10

Negatively charged

Answer 10

having more electrons than protons (more negative charges than positive charges)

Question 11

Neutral

Answer 11

having the same number of protons and electrons

Question 12

Static electricity

Answer 12

a build-up of charge in one place

Question 13

Power supply

Answer 13

a device that can provide an electric current

Question 14

Load

Answer 14

device that uses electrical energy and converts it into other forms of energy

Question 15

Conducting paths

Answer 15

connected series of materials along which an electric current can flow

Question 16

Electric current

Answer 16

a measure of the number of electrons flowing through a circuit every second. An increase in current means an increase in the rate of flow of electrons in the circuit.

Question 17

Filament

Answer 17

coil of wire made from a metal that glows brightly when it gets hot. The filaments in light globes heat up when electricity flows through them.

Question 18

Switch

Answer 18

device that opens and closes the conducting path through which a current flows

Question 19

Resistance

Answer 19

measure of the electrical energy required for an electric current to pass through an object. The energy is changed to heat.

Question 20

Current diagrams

Answer 20

diagram using symbols to show the parts of an electric circuit

Question 21

Series circuit

Answer 21

a circuit with the components joined one after the other in a single continuous loop

Question 22

Parallel circuit

Answer 22

a circuit that has more than one path for electricity to flow through. If one of the paths has a break in it, the others will still work.

Question 23

Ammeter

Answer 23

device used to measure the amount of current in a circuit. Ammeters are placed in series with other components in a circuit.

Question 24

Parallax error

Answer 24

error caused by reading a scale at an angle rather than placing it directly in front of the eye

Question 25

Voltmeter

Answer 25

device used to measure the voltage across a component in a circuit. Voltmeters are placed in parallel with the components.

Question 26

Random errors

Answer 26

an error that occurs due to estimation when reading scales, or when the quantity being measured changes randomly

Question 27

Systematic errors

Answer 27

errors that are consistently high or low due to the incorrect use or limitations of equipment