Edexcel New Specification Core Physic (Topic 5)

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  • Created by: Hannah
  • Created on: 07-05-12 12:38

Current: is the rate of flow of electrons which is measured in Amps. 

Power: is the energy transferred per second and is measured in watts. 

Voltage is an electrical pressure giving a measure of the energy transferred measured in Volts. 

Cell: is a chemical which converts one energy into electrical energy. 

Electromotive force (EMF) this converts the chemical into electrical energy which then supplies it to the circuit measured in volts. . 

Electrons are negatively charged. Negatively charged electrons are repelled out of the negatively terminal of the cell. They then travel around the circuit and are attracted back to the positive terminal. On the way, the electrons give electricity to the components, such as bulbs. Bulbs takes energy from the electrons to convert it into the light energy.

Ammeters are added to a series circuit as the current is the same in every part of the circuit, but in voltmeters are in a parallel circuit to measure the components. In a series circuit current is the same at each point and voltage is shared equally over each component. 

In a parallel circuit current is shared equally down each branch and voltage is the same across each branch. 

Direct Current is a current which can only flow in one direction. 

Alternative Current is the current changing direction 50 times per second (frequency 50 Hz)

Power= current x voltage

Remember when you calculate current the current must stay the same so if you were to increase the voltage, you should increase the power. 

Electricity is created from the movement of the wire in a magnetic field , or the movement of a magnetic field within a coil of wire. This is called electromagnetic induction discovered by Michael Faraday, a British chemist and Physicist in 1831. 

The magnets creates a magnetic field between them. The magnetic field is a force therefore when the wire is moved either backward or forward this force pushes (attract) the electron and a flow of charge, flow of charge is current. 

Electromagnetic induction creates an alternating current (AC). 

The four factors that affect the induced voltage and current are:

  • Stronger magnet…

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