Past Paper Cards Flashcards
Define elastic behavior
Returns to original length or shape once force is removed.
Advantage of 24h orbit satellite
The satellite is always about the same point on the Earth (Geostationary Object).
Charger moved into shade & output power decreases
Longer charging time needed because there is lower current. P = IV
Sources of background radiation
Cosmic radiation, nuclear waste, sources from medical sources, radon gas, some foods like bananas
Effect of beta emission on nucleus
The neutron number decreases by 1 as it changes into a proton, so the atomic number increases by 1.
Why do bubbles expand as they rise towards the surface?
Pressure decreases as depth decreases, since P = hρg. Additional bubbles join together as they rise.
Damage of infrared
Skin burns.
Damage of ultraviolet
Damage to surface cells & blindness.
Why do planets close to the sun take less time to orbit?
They have a smaller orbital path.
Convection current explanation
Air becomes hot. Air expands & becomes less dense, hence it rises.
How can a turbine generate electricity?
Hot air turns turbines, and turbines turn the generator.
KE formula
½ mv^2
What star colour is coolest?
Red
What is reaction force?
The second object exerts an equal and opposite force on the first.
Use of gamma rays
Used to sterilise medical tools because gamma kills bacteria.
Use of X-rays
Used to photograph bones because x-rays can penetrate soft tissues but not bones.
Use of ultraviolet
Used for detecting security ink because it fluoresces with ultraviolet lighting
Use of infrared
Used for optical fibre communication because they can undergo total internal reflection
Use of microwaves
Used for satellite communication because microwaves can penetrate earth’s atmosphere.
Use of radio waves
Used for long-range communications because they can be reflected from the Earth’s atmosphere.
Describe how the average kinetic energy of the gas particles changes when the temperature of the gas increases.
Average kinetic energy increases in direct proportion to kelvin temperature.
Describe doppler effect (object moving away)
Frequency decreases and wavelength increases because wave speed is constant.
Why does fusion need high temperatures?
Hydrogen nuclei repel, so they need a high kinetic energy to get close enough to fuse together.
Define ionisation
Removal of electrons from an atom
