Physics Y09 Aut1 Flashcards
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What are the eight energy stores?
Magnetic, kinetic, thermal (internal), gravitational, chemical, elastic potential, electrostatic, nuclear.
What are the four energy transfers?
Heating, mechanical, electrical, radiation
State the conservation of energy principle.
Energy is never created or destroyed. Only changed from one form to another.
What is dissipated energy?
Wasted energy that is transferred to the surroundings, usually as thermal energy or sound radiation.
Define power and give an equation to calculate power.
P = E ÷ t. It is the rate of which energy is transferred
Give the equation that relates efficiency to power.
Efficiency = useful power output ÷ total power in
Name six renewable energy resources and four non-renewable energy resources.
Renewable: solar, wind, hydroelectric, wave, tidal, biofuels, geothermal Non-renewable: coal, oil, gas, nuclear
What is the difference between renewable and non-renewable energy resources?
Non-renewable energy resources will run out. Renewable energy resources will not.
What’s the difference between a series and a parallel circuit?
A series circuit has only one path for the current to flow; a parallel circuit has more than one.
What is the definition of electrical current?
Electric current is the rate of flow of charge.
What is the equation that links charge, current and time?
Q = I × t
Give the equation that links potential difference, energy and charge.
E = Q × V
Give the equation that links potential difference, current and resistance.
V = I × R
What happens to current in series circuits?
Current is the same everywhere in a series circuit.
What happens to current in parallel circuits?
Current splits at a junction in a parallel circuit.
What happens to potential difference in series circuits?
Potential difference is shared by the components in a series circuit.
What happens to potential difference in parallel circuits?
Potential difference is the same across each branch in parallel
What is the equation for density?
ρ = m ÷ V
How are the particles in a solid arranged?
The particles are touching and vibrate around a fixed pattern.
How are the particles in a liquid arranged?
Particles are touching but not in fixed positions. They are free to flow around.
How are the particles in a gas arranged?
Particles are far apart and move around quickly and randomly.
What are the names of the five state changes?
Melting (solid → liquid), evaporating (liquid → gas), freezing (liquid → solid), condensing (gas → liquid), sublimating (solid → gas/gas → solid).
What is internal energy?
Internal energy is the total kinetic energy and potential energy of all the particles that make up a system.
What is the radius of an atom?
1 × 10-10 m
What are the three subatomic particles?
Protons and neutrons (inside the nucleus) and electrons orbiting around the nucleus.
What is an isotope?
Isotopes have the same number of protons but different numbers of neutrons.
What is the plum pudding model?
An early model of the atom where the atom is a ball of positive charge with negative electrons embedded in it.
Who discovered the neutron?
James Chadwick.
What is a scalar?
A quantity with magnitude (size) but no direction.
What is a vector?
A quantity with magnitude (size) and direction.
What is a contact force?
A contact force is a force that needs to touch to act.
What is a non-contact force?
A non-contact force is a force that does not need to touch to act.
Give 6 examples of contact forces.
Friction, air resistance, tension (elastic) and normal reaction, upthrust, thrust.
Give three examples of non-contact forces.
Gravitational (weight), electrostatic and magnetic.
What is the equation for weight?
W = m × g
What is a resultant force?
A single force that has the same effect as all forces acting together.
What is work done?
It is an energy transfer.
What is the equation for work done?
W = F × s
What does work done against frictional forces cause?
A rise in temperature of the object.
What is the equation for Hooke’s law
F = k × e
What is the relationship between the force applied and the extension of an elastic object.
The extension of an elastic object is directly proportional to the force applied.
What does a wave transfer?
A wave transfers energy from one place to another.
What is the definition of a transverse wave?
The vibration causing a transverse wave is perpendicular to the direction of travel of the wave.
What is the definition of a longitudinal wave?
The vibration causing a longitudinal wave is parallel to the direction of travel of the wave.
What is the amplitude?
The amplitude is the maximum displacement of a wave from its equilibrium position.
What is the wavelength?
The wavelength is the distance from a point on one wave to the same point on the next wave.
What is the frequency?
The frequency is the number of waves passing a point each second.
What is the wave speed equation?
v = f × λ
List the EM waves in order from longest to shortest wavelength.
Radio, microwave, infra-red, visible, ultra-violet, x-ray, gamma.
Which three EM waves are ionising?
Ultra-violet, x-ray and gamma.
What is the danger of ultra-violet radiation?
Increased risk of SKIN cancer
What is the danger of X-rays and gamma ray?
Increased risk of cancer
What are radio waves used for?
Television and radio transmission.
What are microwaves used for?
Satellite communication (as they can travel through ionosphere) and for cooking food.
What is infra-red used for?
Electrical heaters, cooking food and infrared cameras
What is visible light used for?
Fibre optic communications (and our vision!)
What is ultra-violet used for?
Energy efficient lamps, sun tanning.
What are X-rays used for?
Medical imaging and security scanning.
What are gamma rays used for?
Medical treatment (radiotherapy).
Like poles ______, unlike poles ________.
Like poles repel, unlike poles attract.
Is magnetism a contact or non-contact force?
Magnetism is a non-contact force.
What is a permanent magnet?
A permanent magnet produces its own magnetic field.
What is an induced magnet?
An induced magnet becomes a magnet in a magnetic field.
What are the four magnetic metals?
Iron, Nickel, Steel and Cobalt.
Where is the field of a bar magnet strongest?
At the poles and closer to the magnet.
What direction do magnetic field lines go in?
From North to South.
Write the planets in the solar system in order.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
What is a satellite? What are the two types of satellite?
A satellite is something in orbit around an object. A satellite can be natural or artificial.
How is a star formed?
A nebula gets pulled together under gravity. Friction heats hydrogen until the nebula is hot enough for nuclear fusion to happen.
Once a star is formed, how does it reach equilibrium?
The outward force from the radiation produced by fusion is balanced by the inward force of gravity from the mass of the star.
What are the stages in the life cycle of a star of similar size to the sun?
Nebula → Protostar → Main sequence star → Red giant → White dwarf → Black dwarf.
What are the stages in the life cycle of a star much more massive than the sun?
Nebula → Protostar → Main sequence star → Red super giant → supernova → neutron star/black hole
How can the force of gravity lead to changing velocity but unchanged speed.
Velocity is a vector. As an object orbits, its direction changes, so it’s velocity changes.
What happens to the radius of an orbit if the speed increases?
If the speed increases, then the radius of an orbit decreases.
What is red shift?
A light source moving away from stars and galaxies is shifted to longer wavelengths
What does the red shift tell us about the universe?
The red shift tells us that the universe is expanding and that it began from a very small region that was extremely hot and dense.
