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Electricity, Forces and Machines
Yearly exam
38
Science
9th Grade
11/06/2011

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Cards

Term
Electric Current
Definition
The flow of charge, measure in Amps.
Term
Columbs
Definition
The amount of change of one Amp in a second. (C)
Term
Voltage
Definition
The measure of how much electrical energy there is to push charges around a circuit. (V)
Term
Resistance
Definition
The measure of how much a load restricts and reduces the flow of a current. Conducters have little resistance, insulators have a lot. Measured in Ohms (_O_)
Term
Resistor
Definition
Controls the voltage and current of a circuit.
Term
What did Sir Isac Newton do?
Definition
He discovered gravity, and that force=mass+acceleration.
Term
What is Ohms Law?
Definition
In certain objects, if the voltage is doubled in an electric current, the current doubles. E.g Metals and Carbon.
Term
What does V stand for in Ohms Law?
Definition
Voltage drop (in volts)
Term
What does I stand for in Ohms Law?
Definition
The electrical current (in Amps.)
Term
What order is Ohms Triangle?
Definition
V over I x R
Term
What is a Series circuit?
Definition
Each load is included in one circuit. The voltage is shared between the components.
Term
What is a Parallel circuit?
Definition
The current is divided between each of the components, but each branch uses the full voltage of the power supply.
Term
What is an EMR wave made up of?
Definition
An Electric field, and a magnetic field.
Term
What is the distance between 2 Trough and 2 Crest?
Definition
A wavelength.
Term
Name the parts of a sound wave
Definition
Trough, Crest, Amplitude.
Term
What is the difference between a Trough and a Crest?
Definition
A cycle.
Term
What are machines?
Definition
Devices that affect the force and effort required to do a job.
Term
What are pulleys?
Definition
A wheel in which a belt or rope is passed over. It changes the direction of the effort applied to the rope. A block and tackle uses two or more pulleys to reduce the amount of effort.
Term
What is an inclined plane?
Definition
Make it easier to slide or skid a load upwards rather then vertically.
Term
What are gears?
Definition
Gears are a system of toothed wheels that transmit rotary rotation from one point to another.
Term
What is a wheel and axle?
Definition
A wheel and axle combines the effects of a pulley and lever.
Term
What is a lever?
Definition
A lever is a simple machine that uses the turning point of a force to make a task easier.
Term
What are 1st Class levers?
Definition
1st class levers are force multipliers. The force is in the middle. E.g Seesaw
Term
What are 2nd Class Levers?
Definition
Force multipliers. The load is in the centre. E.g Wheelbarrow.
Term
What are 3rd Class levers?
Definition
Speed Multipliers. Effort in the centre. E.g Tweezers, arm and fishing rod.
Term
Explain the process of Reflection
Definition
When light hits a reflective surface, it bounces back. The ray that hits the surface is the incidence ray, and the ray that bounces back is the reflected ray.
Term
Explain Convex Lenses
Definition
Light rays that pass through them meet (converge) at a point. The point where the rays meet is the focal point of the lens.
Term
Explain Concave lenses
Definition
Light rays reflect away (converge) from each other. They have a virtual focal point.
Term
Explain Refraction
Definition
When light slows or speeds as it travels through an object. (Transparent, Translucent)
Term
Explain a Normal Light Beam
Definition
A beam or ray un-affected by another substance.
Term
Explain a boundry beam of light
Definition
An object that interrupts the path of light.
Term
Explain Reflection
Definition
When light bounces back off an object as the same angle that it hit it.
Term
Explain the process of the eye.
Definition
The cornea refracts light before it hits the lens. Before it hits the lens it goes though a hole in your iris called the pupil. The iris controls how much light goes through the pupil and into your eye. The lens bends the light so the image remains clear. The light goes through the retina to the optic nerve so the brain can compress it.
Term
What is the method in Electroplating?
Definition
1. Place the Copper in a beaker.
2. Half fill the beaker with copper sulphate.
3. Connect the iron nail to the positive terminal of a power pack and the copper electrode to the negative terminal.
4. Place a nail in the solution, making sure the two electrodes don't touch.
5. Use 10 volts from the power pack and allow the current to flow for five minutes.
6. The nail should become coated in copper.
Term
What is Mythopia?
Definition
Mythopia is short sightedness. People can see close images, but there long sightedness is poor.
Term
What is Hyperopia?
Definition
Long sightedness. Close up images are blurry.
Term
What happens when white light hits a triangular prism?
Definition
Different colours emerge because each colour of light travels at a slightly different speed, and thus, is refracted at a slightly different angle. It is called dispersion.
Term
Work=what?
Definition
Work (Joules)=Force (Newtons) x Distance
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