Changes in charge, current and potential difference during the charging and discharging of a capacitor are all exponential-type behaviours. Specifically, the current that transfers charge to or from a capacitor (during charging or discharging respectively) is always greatest at first and declines to zero as time increases. During discharging, the charge loss and the drop … Continue reading Charging a Capacitor (analysis)
Key Facts: Electric circuits
Electricity is one of the forms of energy transfer so it is not surprising that the definition of the volt (the unit for measuring potential difference) is the energy carried per unit charge. In symbols, where Q is the symbol for charge, this relationship is written as; V = E / Q It is important … Continue reading Key Facts: Electric circuits
Atoms: Vital Statistics
In a previous article, I recapped the key facts you need to know about atoms. Here we will look at the numerical information you need to remember and the concept of isotopes. The table below lists the essental information you need to know about the three sub-atomic particles; protons, neutrons and electrons. There is an … Continue reading Atoms: Vital Statistics
Energy Transfers in Electric Circuits
The amount of energy transferred in an electric circuit can be calculated by multiplying the current, time and potential difference. This is expressed in the equation given below. Current is measured in amps (amperes), time is in seconds, and potential difference in volts. Remember that the symbol for current is the letter I - not … Continue reading Energy Transfers in Electric Circuits
Electric fields
A field, in physics, is a region of space where one object can affect another object without the two objects touching each other. The most familiar fields are gravitational and magnetic but now we need to gain some understanding of electric fields and their shapes. Let's start with a quick recap of what we know … Continue reading Electric fields
What is Static Electricity?
When work is done on an object, by moving a force through a distance, the object gains energy. As a result, the object might get hotter (gain thermal energy) or accelerate (gain kinetic energy) or be lifted upwards (gain gravitational energy). There is also another possibility; the object could gain electrical energy in the form … Continue reading What is Static Electricity?
Voltage and Current
When you first started learning about circuits, either in primary school or in Y7, you should have been told about voltage and current. These two measurements were probably presented as separate ideas but in fact they both relate to one thing; electrical charge. Voltage relates to the amount of energy given to the charge that … Continue reading Voltage and Current
Static Electricity: Uses and Dangers
It is important that you can describe and explain how static electricity is used, or avoided, in some real-life situations. A good way to recall example uses and dangers is to start from what they have in common; The uses all exploit electrostatic forces, which may either attract or repel objects.The dangers all involve sparks. … Continue reading Static Electricity: Uses and Dangers
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