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55 Cards in this Set
- Front
- Back
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an atom consists of:
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protons, electrons, neutrons
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an atom is electrically ...; that means...
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neutral;
it has the same number of positive charges (protons) as negative charges (electrons) |
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how is static electricity created?
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when you rub two substances together, the friction created makes some of the atoms move from one surface to the other, leaving an imbalance, and making one surface negatively charged and the other positively charged. This imbalance creates static electricity.
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what is a conductor of electricity?
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any substance that will allow electric current to flow through it. A conductor cannot be charged with static electricity.
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What is lightning?
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When small particles of ice inside storm clouds move upwards, past each other, they rub against each other. This movement causes the clouds to become charged. When they pass over the Earth, the opposite charge is induced in the ground. If the charge is large enough, a flash of lightning occurs between the cloud and the ground or between clouds.
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Like charges.... and opposite charges....
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repel....attract
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What is the circuit symbol for a bulb?
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This!
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What is a fossil fuel?
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A fuel that was 'made' millions of years ago from the dead remains of plants (COAL) and animals (GAS & OIL)
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what is the circuit symbol for a motor?
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this!
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What is the circuit symbol for a buzzer?
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This!
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What is the circuit symbol for an ammeter?
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This!
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What is the circuit symbol for a cell?
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This!
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What is the circuit symbol for a diode?
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This!
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What is the circuit symbol for a fuse?
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This!
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What is the circuit symbol for a LDR?
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This!
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What is the circuit symbol for a LED?
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This!
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What is the circuit symbol for a relay?
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This!
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What is the circuit symbol for a resistor?
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This!
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What is the circuit symbol for a SPDT switch?
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This!
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What is the circuit symbol for a SPST switch?
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This!
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What is the circuit symbol for a variable resistor?
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This!
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What is the circuit symbol for a voltmeter?
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This!
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the flow of current in a circuit is the .....
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movement of electrical charge.(electrons)
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in a series circuit the current flows in a....
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continuous loop.
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in a parallel circuit the current.....
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splits into separate branches.
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What is the unit of force?
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Newtons (N)
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What do forces do?
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Make things speed up, slow down or change shape, maintain at rest
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Which direction do frictional forces act?
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Oppose motion
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Two ways to reduce friction are:
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1. Oil
2. Streamline shape 3. Bearings |
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What affects braking distances of cars?
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Speed, road surface, drink
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Upthrust =
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Weight of water displaced
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What is the unit of mass?
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Kg or g
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Springs: What is the force proportional to?
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the load or force
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What happens to the extension if you double the load with parallel springs?
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half the extension
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At what point does a spring not stretch evenly?
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at its elastic limit
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How many g in a kg?
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1,000
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How many m in a km?
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1,000
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What is current measured in?
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Amps (A)
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What is the equation and units for speed?
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Speed = distance over time (m/s or km/h)
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What is the equation and units for pressure?
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Pressure = Force over area (N/cm squared)
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What is the equation and units for Moment?
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Moment = Force x distance (Nm)
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What is the equation and units for Density?
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Density = mass over volume (kg/m cubed or g/cm cubed)
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Air or water pressure increases with
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Depth
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To increase pressure, ........ the force.
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increase
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To increase pressure, ....... the area
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decrease
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How do you measure the volume of an irregular shaped object?
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Place it in a measuring cylinder with a known volume of water. the difference is the volume of the object.
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What is the density of water?
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1g/cm cubed
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Heat always flows from a hot object to a ....
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cold object (never the opposite)
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What is conduction?
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Heat energy passed along a solid by adjacent vibrating molecules.
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What is convection?
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Heating causes expansion, density falls, liquid or gas (not solid) rises -- convection current
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What is radiation?
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as with light - through air or space
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Which surface is radiation greates to AND from?
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Black surfaces (least from white/silver)
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A household radiator mainly heats by what type of heat transfer?
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convection
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Name five ways that heat is lost in a house.
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windows - double glazing
walls - cavity walls insulation floors - underlay and carpets roof - loft insulation draughts - draught excluders |
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What is the law of conservation of energy?
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energy cannot be created or destroyed - it merely changes from one form to another
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