Electrical Power
The power of an appliance is the energy that is transferred per second. Electric power is the rate, per unit time at which electrical energy is transferred by an electric circuit.
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Density
Density is a measure of how compact the particles are in a substance. Density is defined as the mass per unit volume.
Specific Latent Heat
Specific latent heat is the energy needed to change the state of a substance.
Half Life
The radioactivity of a sample decreases over time. Half life is a measurement of this decrease.
Gravitational Potential Energy
Lifting an object in a gravitational field transfers energy into the objects gravitational energy store. Gravitational potential energy is the energy an object has due to its height above Earth.
Efficiency
The efficiency of a device is the proportion of input energy that is converted to useful energy.
Energy Transformed
The potential difference between two points is the energy transferred per unit charge. An electrical circuit is an energy transformation device.
Forces and Work Done
The unit for work done is the joule (J), or Newton meter (N-m). One joule is equal to the amount of work that is done when 1 N of force moves an object over a distance of 1 m.
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Momentum
All moving objects have momentum. Forces can cause changes in momentum. The total momentum in a collision or explosion is conserved and stays the same. Car safety features absorb energy involved in a crash they slow down the collision thus reducing the force of impact.
Transformers
A transformer is an piece of electrical apparatus which will increase or decrease the voltage in an alternating current. It can be designed to "step up" or "step down" voltages and is based on the magnetic induction principle.
