Physics Units 1-4

Question 1

How do you calculate the amount of elastic potential energy stored in a spring?

Answer 1

E = ½ ke²

Question 2

What happens to the gravitational potential energy of an object as it falls?

Answer 2

It changes to kinetic energy

Question 3

What is specific heat capacity?

Answer 3

The energy required to raise the temperature of one kilogram of the substance by 1⁰C

Question 4

What is power?

Answer 4

Work done per unit time OR energy transferred per unit time

Question 5

What is a power of one watt equal to?

Answer 5

1 J/s

Question 6

What is the principle of conservation of energy?

Answer 6

Energy cannot be created or destroyed just transformed from one form into another

Question 7

How could you reduce unwanted energy transfers in machinery with moving parts?

Answer 7

Oil/lubricate

Question 8

How could you reduce unwanted energy transfer from a cup of coffee?

Answer 8

Insulate

Question 9

Name 2 renewable energy resources available for use on earth.

Answer 9

Wind/wave/tidal/solar etc

Question 10

Name 2 non-renewable energy resources available for use on earth.

Answer 10

Coal/oil/gas/nuclear

Question 11

What is meant by a renewable energy resource?

Answer 11

Will not run out

Question 12

What is electrical current?

Answer 12

Flow of charge/flow of electrons

Question 13

What do you know about the current at any point in a series circuit?

Answer 13

It is the same

Question 14

What happens to the resistance of an LDR as light intensity increases?

Answer 14

Decreases

Question 15

What happens to the resistance of a thermistor as one temperature increases?

Answer 15

Decreases

Question 16

Is mains electricity ac or dc?

Answer 16

a.c.

Question 17

What is its frequency?

Answer 17

50Hz

Question 18

What is its p.d?

Answer 18

230V

Question 19

What is the difference between ac and dc?

Answer 19

a.c. - changes direction d.c. - one direction

Question 20

What colour are the insulation coverings on live, neutral and earth wires?

Answer 20

live - brown, neutral - blue, earth - green & yellow

Question 21

What is the earth wire there for?

Answer 21

As a safety device

Question 22

What is the p.d. between the live wire and the earth?

Answer 22

230V

Question 23

When does the earth wire carry a current?

Answer 23

If there is a fault

Question 24

What are the 2 different equations to calculate power in an electrical circuit?

Answer 24

Power = IV

Power = I²R

Question 25

What is the National Grid?

Answer 25

A system of cables and transformers linking power stations to consumers

Question 26

What does a step up transformer do?

Answer 26

Increases voltage

Question 27

How does an insulator become charged when rubbed with another insulating material?

Answer 27

Friction causes electrons to be removed from one and given to the other

Question 28

What is density?

Answer 28

Mass per unit volume

Question 29

Why is a solid more dense that a gas?

Answer 29

Particles are closer together

Question 30

What is internal energy?

Answer 30

Total potential and kinetic energy of all the particles

Question 31

What is specific latent heat?

Answer 31

The energy required to change the state of one kilogram of a substance without a change in temperature

Question 32

What happens to the motion of molecules in a gas if you increase the temperature?

Answer 32

Move faster

Question 33

What happens when you do work on a gas?

Answer 33

Increase internal energy / increase temperature

Question 34

What is the radius of an atom?

Answer 34

1x10-10 m

Question 35

How many times smaller is the radius of a nucleus than an atom?

Answer 35

10,000 times

Question 36

Electrons are found in different what?

Answer 36

Energy levels

Question 37

Why are atoms neutral?

Answer 37

Same number of protons and electrons

Question 38

What is the atomic number of an element?

Answer 38

Number of protons

Question 39

What is the mass number of an element?

Answer 39

Number of protons and neutrons

Question 40

What is an isotope?

Answer 40

Atoms of the same element with the same number of protons and different number of neutrons

Question 41

How do you form a positive ion?

Answer 41

Lose electrons

Question 42

Why do some atoms decay?

Answer 42

They are unstable

Question 43

What is meant by the activity of an atom?

Answer 43

The rate at which a source or unstable nuclei decay

Question 44

Which type of radiation is the most ionising?

Answer 44

Alpha

Question 45

Which type of radiation is the least penetrating?

Answer 45

Alpha

Question 46

What is an alpha particle?

Answer 46

2 protons and 2 neutrons / He nucleus

Question 47

What is a beta particle?

Answer 47

Fast moving electron

Question 48

What is gamma radiation?

Answer 48

Electromagnetic radiation

Question 49

What is the half-life of a radioactive isotope?

Answer 49

The time it takes for half of the nuclei in a sample to decay

Question 50

What is radioactive contamination?

Answer 50

The unwanted presence of materials containing radioactive atoms on other materials

Question 51

What is irradiation?

Answer 51

The process of exposing an object to nuclear radiation

Question 52

Name a source of background radiation?

Answer 52

Cosmic rays / rocks / fallout from nuclear weapons / nuclear accidents

Question 53

Name a use of nuclear radiation in medicine?

Answer 53

Exploration of internal organs / control or destruction of unwanted tissue

Question 54

What is nuclear fission?

Answer 54

Splitting of large nuclei

Question 55

What usually needs to happen for fission to occur?

Answer 55

Neutron to be absorbed

Question 56

What is nuclear fusion?

Answer 56

Joining of small nuclei