100 or so Paper 2 IGCSE Physics facts Flashcards
What is the difference between scalar and vector quantities?
Vectors have a direction as well as a magnitude (size)
Magnets can attract?
Magnetic materials (and other magnets too)
What are the disadvantages of hydroelectric power?
Floods a large area,
disrupts people and animals
Name some vector quantities
Velocity,
displacement,
acceleration,
force,
momentum,
moment,
current
What is the relationship between input and output power of a transformer?
Pprimary = Psecondary
IpVp = IsVs
What experiment can be done to demonstrate charging by friction?
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.
Energy transferred per unit charge is known as?
Voltage
Magnets can attract or repel?
Other magnets
If the kelvin temperature of a gas doubles, what happens to the pressure it exerts?
Pressure doubles too
What are some advantages of digital signals?
Can carry more information
Easier to clean the signal (remove noise)
How can electrostatic charge cause a fire at a petrol station.
Charge builds up on car while driving
a spark when person touches car
+ fuel vapour = explosion
What are the advantages of hydroelectric power?
Renewable,
no air pollution,
low running costs, no fuel costs
Name some scalar quantities
Speed,
mass,
volume,
time,
energy,
charge,
pressure,
power
What is the difference between analogue and digital signals
Analogue signals can have any value.
Digital signals can ONLY be on or off
What are the advantages of geothermal power?
Renewable,
no air pollution,
low running costs, no fuel costs
Why is iron used as the core for a transformer?
Soft magnetic material; gains and loses magnetism easily.
What is conservation of momentum?
Momentum before a collision (or explosion) is equal to the momentum after.
Assuming no external forces act.
Describe the arrangement and motion of particles in a gas
No pattern;
Able to move freely/fast;
Larger space between particles;
What has the following magnetic field shape?
Field around a current carrying wire
What are the advantages of solar cells?
Renewable,
no air pollution,
low running costs, no fuel costs
What are the advantages of wind power?
Renewable,
no air pollution,
low running costs, no fuel costs
Which support provides more force? Why?
Moments about the person are equal.
A closer to person, so needs bigger force to provide same moment as B.
What is happening to this wave?
Diffraction; wave is spreading out
Describe the arrangement and motion of particles in a liquid
Irregular pattern;
Able to move over/past other particles;
Little space between particles;
What are the advantages of nuclear power?
Reliable (not weather dependent),
already established,
high power output
How does bending you knees help prevent injury?
Increases collision time,
lower deceleration (a=V/t),
lower force (F=ma)
What has the following magnetic field shape?
Field around a flat coil
(looks like an owl)
Why is the iron core in a transformer laminated?
Prevents eddy currents;
stops heating;
keeps efficiency high.
What are the general advantages of renewable sources of power?
Renewable,
no air pollution,
low running costs, no fuel costs
What change of state happens during condensing?
gas to liquid
What change of state happens during melting?
solid to liquid
A charged partical experience no force due to a magnetic field when?
Moving parallel to field
What sort of electricity is needed to make transformers work?
AC; current must change direction so magnetic field keeps changing direction
Magnetically hard materials….
Are difficult to magnetise but keep their magnetism
What is the missing force?
What force is felt by the charged particle
No force felt as particle is moving parallel to field.
What is Newton’s third law?
If object A exerts a force on object B, object B exerts an equal and opposite force on object A
More turns on the secondary coil is what sort of transformer?
Step up; voltage is bigger across the secondary coil
Give some useful uses of electrostatic charges
Paint spraying,
Chimney precipitator (smoke cleaner),
Photocopier,
Ink Jet Printer
How does a material gain a negative electrostatic charge?
Object gains electrons to gain a negative charge
What are the disadvantages of geothermal power?
Only works in very specific places,
deep drilling difficult and expensive
What are the advantages of fossil fuels?
Reliable (not weather dependent),
already established,
high power output
What are the advantages of solar heating systems?
Renewable,
no air pollution,
low running costs, no fuel costs
Maximum diffraction happens when the gap size is?..
similar to the wavelength
How can fires be prevented when refuelling aircraft (linked to electrostatic charge)
Attach Earthing strap (to discharge aircraft) before beginning to refuel
What are the disadvantages of solar heating systems?
Unreliable (doesn’t work at night),
may need additional boiler to produce hot water
What is the Newton’s third law pair
Why are step up and step down transformers used in the National Grid?
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.
Why doesn’t DC work for transformers?
DC doesn’t change direction so the magnetic field is constant
How does a material gain a positive electrostatic charge?
Object loses electrons to gain a positive charge
What are the disadvantages of solar cells?
Unreliable (doesn’t work at night or when cloudy),
large area needed to replace a typical power station,
inefficient
Magnetically soft materials…
Are easy to magnetise but lose their magnetism quickly
What change of state happens during boiling?
liquid to gas
What are the general disadvantages of renewable sources of power?
Unreliable (weather dependent),
large amount of land needed to replace a typical power station
How does a stretching seatbelt reduce injury
Increases collision time,
lower deceleration (a=V/t),
lower force (F=ma)
The frequency of a sound wave is linked to its?.
pitch
The amlitude of a sound wave is linked to its?.
volume
What are the disadvantages of nuclear power?
Produces long lasting radioactive waste which must be securely stored,
mining hazardous
What change of state happens during freezing?
liquid to solid
What is the resultant force in each case?
What are the benefits of using electrostatically charged spray paint
Paint has same charge so repels = fine mist, no clumps.
Object has opposite charge, attracts paint into corners and around the back
One volt is equal to one?..
One joule per coulomb
What is the Newton’s third law pair
How are electromagnets made?
A coil of wire around an iron core
When two objects with a positive electrostatic charge are close together they?
Repel as like charges repel
More turns on the primary coil what sort of transformer?
Step down; voltage is bigger across the primary coil
How can digital signals carry more information?
Multiplexing (e.g. different coloured light in fibre optics)
Increase the frequency of the transmitter
How can you find the frequency of a sound wave from an oscilloscope trace
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
What is the relationship between kelvin temperature of a gas and average kinetic energy its molecules?
Kelvin temperature is directly proportional to average kinetic energy.
Doubling the temperature (in kelvin!) doubles KE
Why is a current induced in the secondary coil?
The secondary coil sees a changing magnetic field;
electrons experience a force and move;
which induces a current
What are the disadvantages of wind power?
Unreliable (only works when windy),
needs lots of land,
visual pollution, a large number needed to replace a typical power station
What is the relationship between input and output voltages and the no. of turns on each coil?
What equation links momentum, mass and velocity?
Momentum = mass x velocity
How can electrostatic charge be used to clean smoke in a chimney?
Smoke particles charged by wires and attracted to charged plates
What can happen to waves when they pass an edge or go through a gap?
Diffraction; waves spread out
Describe the structure of a transformer
Two coils of wire wrapped around a laminated iron core
What two pieces of equipment are needed to display a sound wave?
Microphone and oscilloscope
What has the following magnetic field shape?
Field around a solenoid (same shape as a bar magnet)
What are the disadvantages of fossil fuels?
Release CO2 and air pollution, mining hazardous
How can magnetism be induced in a magnetic material?
Placing a magnet close to a magnetic material will induce magnetism in the magnetic material
Describe the arrangement and motion of particles in a solid
Regular pattern OR close packed;
Vibration in position;
Little space between particles
