100 or so Paper 2 IGCSE Physics facts

Question 1

What is the difference between scalar and vector quantities?

Answer 1

Vectors have a direction as well as a magnitude (size)

Question 2

Magnets can attract?

Answer 2

Magnetic materials (and other magnets too)

Question 3

What are the disadvantages of hydroelectric power?

Answer 3

Floods a large area,

disrupts people and animals

Question 4

Name some vector quantities

Answer 4

Velocity,

displacement,

acceleration,

force,

momentum,

moment,

current

Question 5

What is the relationship between input and output power of a transformer?

Answer 5

P_primary = P_secondary

I_pV_p = I_sV_s

Question 6

What experiment can be done to demonstrate charging by friction?

Answer 6

Rub a plastic rod with a cloth, show charge on coulombmeter or repel/attract other charged things.

Rub a balloon on jumper / hair stick to wall.

Question 7

Energy transferred per unit charge is known as?

Answer 7

Voltage

Question 8

Magnets can attract or repel?

Answer 8

Other magnets

Question 9

If the kelvin temperature of a gas doubles, what happens to the pressure it exerts?

Answer 9

Pressure doubles too

Question 10

How can electrostatic charge cause a fire at a petrol station.

Answer 10

Charge builds up on car while driving

a spark when person touches car

+ fuel vapour = explosion

Question 11

What are the advantages of hydroelectric power?

Answer 11

Renewable,

no air pollution,

low running costs, no fuel costs

Question 12

Name some scalar quantities

Answer 12

Speed,

mass,

volume,

time,

energy,

charge,

pressure,

power

Question 13

What are the advantages of geothermal power?

Answer 13

Renewable,

no air pollution,

low running costs, no fuel costs

Question 14

Why is iron used as the core for a transformer?

Answer 14

Soft magnetic material; gains and loses magnetism easily.

Question 15

What is conservation of momentum?

Answer 15

Momentum before a collision (or explosion) is equal to the momentum after.

Assuming no external forces act.

Question 16

Describe the arrangement and motion of particles in a gas

Answer 16

No pattern;

Able to move freely/fast;

Larger space between particles;

Question 17

What has the following magnetic field shape?

Answer 17

Field around a current carrying wire

Question 18

What are the advantages of solar cells?

Answer 18

Renewable,

no air pollution,

low running costs, no fuel costs

Question 19

What are the advantages of wind power?

Answer 19

Renewable,

no air pollution,

low running costs, no fuel costs

Question 20

Which support provides more force? Why?

Answer 20

Moments about the person are equal.

A closer to person, so needs bigger force to provide same moment as B.

Question 21

Describe the arrangement and motion of particles in a liquid

Answer 21

Irregular pattern;

Able to move over/past other particles;

Little space between particles;

Question 22

What are the advantages of nuclear power?

Answer 22

Reliable (not weather dependent),

already established,

high power output

Question 23

How does bending you knees help prevent injury?

Answer 23

Increases collision time,

lower deceleration (a=V/t),

lower force (F=ma)

Question 24

What has the following magnetic field shape?

Answer 24

Field around a flat coil

(looks like an owl)

Question 25

Why is the iron core in a transformer laminated?

Answer 25

Prevents eddy currents; stops heating; keeps efficiency high.

Question 26

What are the general advantages of renewable sources of power?

Answer 26

Renewable, no air pollution, low running costs, no fuel costs

Question 27

What change of state happens during condensing?

Answer 27

gas to liquid

Question 28

What change of state happens during melting?

Answer 28

solid to liquid

Question 29

A charged partical experience no force due to a magnetic field when?

Answer 29

Moving parallel to field

Question 30

What sort of electricity is needed to make transformers work?

Answer 30

AC; current must change direction so magnetic field keeps changing direction

Question 31

Magnetically hard materials....

Answer 31

Are difficult to magnetise but keep their magnetism

Question 32

What is the missing force?

Answer 32

Question 33

What force is felt by the charged particle

Answer 33

No force felt as particle is moving parallel to field.

Question 34

What is Newton's third law?

Answer 34

If object A exerts a force on object B, object B exerts an equal and opposite force on object A

Question 35

More turns on the secondary coil is what sort of transformer?

Answer 35

Step up; voltage is bigger across the secondary coil

Question 36

Give some useful uses of electrostatic charges

Answer 36

Paint spraying, Chimney precipitator (smoke cleaner), Photocopier, Ink Jet Printer

Question 37

How does a material gain a negative electrostatic charge?

Answer 37

Object gains electrons to gain a negative charge

Question 38

What are the disadvantages of geothermal power?

Answer 38

Only works in very specific places, deep drilling difficult and expensive

Question 39

What are the advantages of fossil fuels?

Answer 39

Reliable (not weather dependent), already established, high power output

Question 40

What are the advantages of solar heating systems?

Answer 40

Renewable, no air pollution, low running costs, no fuel costs

Question 41

How can fires be prevented when refuelling aircraft (linked to electrostatic charge)

Answer 41

Attach Earthing strap (to discharge aircraft) before beginning to refuel

Question 42

What are the disadvantages of solar heating systems?

Answer 42

Unreliable (doesn't work at night), may need additional boiler to produce hot water

Question 43

What is the Newton's third law pair

Answer 43

Question 44

Why are step up and step down transformers used in the National Grid?

Answer 44

Voltage stepped up (e.g 100x); Current drops by the same amount (100x lower); less power loss due to heating; Stepped down to be safe in homes.

Question 45

Why doesn't DC work for transformers?

Answer 45

DC doesn't change direction so the magnetic field is constant

Question 46

How does a material gain a positive electrostatic charge?

Answer 46

Object loses electrons to gain a positive charge

Question 47

What are the disadvantages of solar cells?

Answer 47

Unreliable (doesn't work at night or when cloudy), large area needed to replace a typical power station, inefficient

Question 48

Magnetically soft materials...

Answer 48

Are easy to magnetise but lose their magnetism quickly

Question 49

What change of state happens during boiling?

Answer 49

liquid to gas

Question 50

What are the general disadvantages of renewable sources of power?

Answer 50

Unreliable (weather dependent), large amount of land needed to replace a typical power station

Question 51

How does a stretching seatbelt reduce injury

Answer 51

Increases collision time, lower deceleration (a=V/t), lower force (F=ma)

Question 52

The frequency of a sound wave is linked to its?.

Answer 52

pitch

Question 53

The amlitude of a sound wave is linked to its?.

Answer 53

volume

Question 54

What are the disadvantages of nuclear power?

Answer 54

Produces long lasting radioactive waste which must be securely stored, mining hazardous

Question 55

What change of state happens during freezing?

Answer 55

liquid to solid

Question 56

What is the resultant force in each case?

Answer 56

Question 57

What are the benefits of using electrostatically charged spray paint

Answer 57

Paint has same charge so repels = fine mist, no clumps. Object has opposite charge, attracts paint into corners and around the back

Question 58

One volt is equal to one?..

Answer 58

One joule per coulomb

Question 59

What is the Newton's third law pair

Answer 59

Question 60

How are electromagnets made?

Answer 60

A coil of wire around an iron core

Question 61

When two objects with a positive electrostatic charge are close together they?

Answer 61

Repel as like charges repel

Question 62

More turns on the primary coil what sort of transformer?

Answer 62

Step down; voltage is bigger across the primary coil

Question 63

How can you find the frequency of a sound wave from an oscilloscope trace

Answer 63

Measure time period T (of one wave) Use f = 1/T (careful with milli seconds) e.g T = 3ms so f = 1/0.003 = 333Hz

Question 64

What is the relationship between kelvin temperature of a gas and average kinetic energy its molecules?

Answer 64

Kelvin temperature is directly proportional to average kinetic energy. Doubling the temperature (in kelvin!) doubles KE

Question 65

Why is a current induced in the secondary coil?

Answer 65

The secondary coil sees a changing magnetic field; electrons experience a force and move; which induces a current

Question 66

What are the disadvantages of wind power?

Answer 66

Unreliable (only works when windy), needs lots of land, visual pollution, a large number needed to replace a typical power station

Question 67

What is the relationship between input and output voltages and the no. of turns on each coil?

Answer 67

Question 68

What equation links momentum, mass and velocity?

Answer 68

Momentum = mass x velocity

Question 69

How can electrostatic charge be used to clean smoke in a chimney?

Answer 69

Smoke particles charged by wires and attracted to charged plates

Question 70

What can happen to waves when they pass an edge or go through a gap?

Answer 70

Diffraction; waves spread out

Question 71

Describe the structure of a transformer

Answer 71

Two coils of wire wrapped around a laminated iron core

Question 72

What two pieces of equipment are needed to display a sound wave?

Answer 72

Microphone and oscilloscope

Question 73

What has the following magnetic field shape?

Answer 73

Field around a solenoid (same shape as a bar magnet)

Question 74

What are the disadvantages of fossil fuels?

Answer 74

Release CO₂ and air pollution, mining hazardous

Question 75

How can magnetism be induced in a magnetic material?

Answer 75

Placing a magnet close to a magnetic material will induce magnetism in the magnetic material

Question 76

Describe the arrangement and motion of particles in a solid

Answer 76

Regular pattern OR close packed; Vibration in position; Little space between particles