What would have happened if there were no electricity in the world? The world would have been without light, heating or cooling systems, internet, television, and what-not. In short, the world would have been a dull place without electricity.

You'd be surprised to know electricity didn't exist in ancient times. In fact, primitive people lived for centuries without it. They used firewood and candlelight instead.

With time, many scientific breakthroughs in physics, such as electricity, changed how the world worked.

Today, physics holds a key place in academia because humans have learned its importance.

For example, in the United States of America, the SAT exam's physics subject test carries a lot of weightage. The subject includes various topics and sub-topics that allow students to solve various physics problems effortlessly. Not only that, with a high SAT score in the Physics SAT, you can also get into any college of your choice easily.

You just need to have a good grasp of different physics lessons such as energy, electricity, atomic structures, waves, forces, magnetism, and electromagnetism, etc.

Just as UK students need help in successfully passing their GCSE Physics subject, you need help in clearing your SATs with top scores.

So, if you want loads of knowledge about electricity for your SAT prep, read on!

Electric Circuits (EC)

EC Symbols

An electric current has several symbols you can use to identify its various components as illustrated in the image below:

studying electricity
Electronic circuit symbols are used to show various electronic functions and devices, including batteries, resistors, wires, etc. They can be studied to better understand an electric diagram. (Source: iStock)
  • Switch: This component is used for turning the circuit off and on.
  • Fixed Resistor: It restricts the flow of current and includes a uniform resistance.
  • Lamp: A lamp lights up when the current provides heating.
  • Thermistor: Its resistance can vary. It increases when there's low temperature and decreases when there's high temperature. Mostly, it's used in home smoke alarms.
  • Semiconductor diode: It only allows the flow of electric current in one direction.
  • Variable Resistor: It's used mainly for volume control and dimmer switches.
  • Light-dependent Resistor: The resistance is based solely on factors that affect a change in lighting. For instance, the resistance is high when the light remains low and decreases when the light remains high. It is mainly used in automatic lights or camera sensors.

Electric Current And Charge

Electric current can be divided into two main types: direct current and alternating current. In the direct current, electrons flow in one direction around the circuit, whereas, in the alternating current, their flow and direction constantly change.

The electric charge consists of electrons or energy that passes from one form to another via various modes such as induction, conduction, etc. It's measured in coulomb (C), which has around 6.25*10^18 electrons.

All of this information is very crucial for your physics exam for the SAT.

The electric current is significant for the circuit because it lets the energy transfer and gets the electrical work done when it flows. The equation used to measure the quantity of charge passing through a circuit is:

Charge = current x time (or Q = I x t)

The measurement of the above units is done in the following manner:

  • Charge (Q) = coulomb
  • Current (I) = ampere
  • Time (t) = seconds

Potential Difference

With Superprof physics SAT prep, students will also cover the concept of potential difference – the difference between two locations (points) on the circuit denoting how much energy is transferred, in detail.

A voltmeter is usually placed along the component required to be measured. To calculate the potential difference, you can use the following equation:

Potential difference = energy/charge or (V= E/Q)

The measurement of the above units is done in the following manner:

  • Potential difference (V) = volt
  • Energy (E) = joules
  • Charge (Q) = coulomb

Series Circuit

In a series circuit, two or more than two resistors are set up so that current passes from all of them at once.

Parallel Circuits

Students will learn in depth about each separate sub-topic within the main topic of electricity for the SAT physics test. For instance, under parallel circuits, students will learn several specific details, such as how the total current is divided between each component.

Students will acquire this type of knowledge through diagrams and by testing numerous formulae and equations.

Electric Power And Energy

Once the electrons flow through the wires and collide with atoms or ions (read more in-depth about atomic structure here), they generate heat. This happens mainly because when the collision occurs, it produces vibration, which raises the wire's temperature, and hence there is heat.

Practical Exercises

Students learn all of the information above using practical exercises listed below:

  • Probe current-voltage graphs: All students observe a diagram series to finish all nine steps.
  • Probe resistor networks: This exercise tells students there are more methods to probe a resistor network. All pupils note down the current and potential difference in a precise manner. Plus, they have to use proper ways and apparatus so the potential difference can be measured correctly.
  • Probe elements affecting the resistance: Students have to probe how the change in the wire's length affects the resistance.

Electricity is generated by energy and power, which transports through waves. You will learn all you need to know about waves in your SAT prep.

Alternating Current (AC) Power

parts of a plug
After studying the electricity topic in your Physics SAT, not only you'll achieve a high score in the SAT exam, but you will also look at the household plugs in a much different way! (Source: pixabay)

All of us require electricity in homes and offices to cool, heat, and power our appliances. On the voltage-time graph, the direct current appears in the form of a straight line, while the alternating current appears in the form of a curve – which constantly changes between negative and positive voltages.

All students learn that the United States of America generates AC power at 60 Hertz, which is sent to homes at 240 Volts.

Every household has plugs connecting several common devices to AC power. These plugs have cables made of copper wires. They are known as good conductors. Plus, the wires are plastic-coated and hence work as good insulators as well.

The plug includes several sections, and each section has a different function to perform listed as follows:

  • Outer insulation: It prevents any harmful accident. The wires are securely wrapped with additional plastic insulation.
  • Livewire: It is made of copper wire with a brown plastic coating.
  • Cable grip: It keeps the cable in its position, tight and firm.
  • Fuse: It's made of ceramic or glass. It has a thin wire that melts when the current is extremely high. If it's melted, there's no further flow of current in the circuit.
  • Ground wire: It is a copper wire coated with plastic, and it provides an uninterrupted flow to the current to move from the device towards the ground if there's some fault. It saves a person from accidentally getting electrocuted.
  • Neutral wire: It is a copper wire with a blue plastic coating that ensures the circuit's completion.

Electrical Appliances

Electrical appliances can transfer the energy from store to store (this happens only when the other store is hotter). The energy being transferred is based on time and power. Use the following equation to calculate it:

Energy = power x time (or E = P x t)

The measurement of the above units is done in the following:

  • Energy (E) = joules
  • Power (P) = watts
  • Time (t) = seconds

Master this and more concepts like forces with Superprof physics tutor!

Static Electricity

the power of static
A Van de Graaff generator – an electrostatic generator – produces a positive charge and, an individual does not have to touch it to feel the effects.  (Source: Visual Hunt)

Like rubbing two different things together, the charged particles' movement creates electrical effects such as lighting, small shocks, and sparks.

Atoms contain tiny particles like neutrons, protons, and electrons, and are present in every matter (read more about particles of matters here). Within that, the electrons carry a negative charge, while the protons carry a positive charge.


When insulating materials come together, they create friction. For instance, if you take polythene and rub it against a duster, it causes electrons to get extra energy.

Insulators obstruct electrons from marching forward. Thus, the charge remains static. The repulsion and attraction properties are utilized to prove whether there is any charged object or not. For this, always remember, the same charges repel, while the opposites attract.

Electric Fields

Every charged object carries the electric field near them in various forms. The electric field is a physical field around every electric charge that exerts a force on the rest of the charges within that field – either repelling or attracting them.

Sample Electricity Exam Questions

A SAT subject test, including the physics test, is based on multiple-choice questions (MCQs). Though MCQs might seem easy, they can cause quite an issue when all choices are similar in one way or another.

When students learn the electricity topic in their Physics SAT syllabus, it enhances their overall understanding of the subject well enough to attempt any number of confusing MCQs.

If you are interested in learning about more physics topics, check out this article on space physics.

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