Electricity is needed for our daily life. You just imagine all the things that use electricity 24 hours 7 days a week. With electricity playing a big role in our lives we needed people studying it. Those who are thinking about enrolling in a physics class in high school will cover electricity as a topic.
Students in Canada can start to enroll in a physics class in grade 11 or 12. Many students may be unsure if physics is right for them. It can broad a subject that covers many different topics. We've created a series of articles that relate to the syllabus for high school physics. Each article looks at a topic that is under physics. This article looks at electricity. Through the study of Physics electricity can be thoroughly understood by students of all ages. Superprof is here to analyze the four sections covered in the High School Physics subject.
Electric circuits are usually the basis of all beginner physics classes. Understanding electric circuits can serve as a basis for your understanding of electricity. It's important to understand circuits before learning other things.
Electrical Circuit Symbols
There are various symbols used to identify the different components that can be found in an electric circuit. Here are the most commonly observed symbols on an electric circuit:
Some of the most common components on an electric circuit include the following:
- Switch: a very simple component used to turn a circuit on and off.
- Lamp: an electric current heats a bulb so that it can give out some light.
- Fixed Resistor: restricts or limits the flow of electrical current. The fixed resistor has a resistance that will never change.
- Variable Resistor: used for some dimmer switches and volume controls. Moving the position of the slider causes it to change.
- Thermistor: resistance depends on the temperature. When the temperature is low the resistance is elevated and when the temperature is high the resistance decreases. Used in fire alarms or thermostats in the house.
- Light-dependent resistor (LDR): resistance depends completely on light intensity. On lower light levels, the LDR has a higher resistance and as the light increases the resistance decreases. Used as a sensor in cameras or automatic lights.
- Semiconductor diode: allows current to flow in only one direction and it will never flow in the opposite direction.
Electrical Charge and Current
After understanding circuits learning about electrical charges and current will be the next step. There are two types of electric currents: direct and alternating current. The basis of these two currents is direct current is electrons that constantly flow in the same direction around a current. Alternating current the direction and flow of electrons constantly change direction. Currents are essential to all circuits. Current allows for the work to be transferred. A very simple equation can be used to calculate the amount of charge going through a point of the circuit:
charge= current x time or Q = I x t
The charge (Q) is measured in coulombs, current (I) is measured in amps and time (t) is measured in seconds.
Students also learn a lot more about potential difference which is the measure of how much energy is transferred between two points on a circuit. To measure the potential difference of an electric circuit a voltmeter needs to be placed in parallel with the component that is being measured.
The potential difference can be calculated by using a basic equation such as the following:or
(Both images are courtesy of bbc.com/bitesize/guides)
The potential difference (V) is measured using volts, energy (E) is calculated by using joules and charge (Q) is measured in coulombs.
Series circuits are also analyzed which is the fact that electrical components are connected one after another in a single loop. The circuit rules include the fact that an electron will pass through every component on its way around the circuit. If a bulb is broken the current will not be able to go around the whole circuit. Think of Christmas lights. If one light is out on series of bulbs and the rest of the lights are out it is using a series circuit.
While learning about parallel circuits, students acquire useful knowledge on the subject such as the fact that the total current provided is divided between the components on different loops, potential difference is spread equally and is the same across each loop and the total resistance of the electric circuit can be reduced as the current can follow different paths. There are lots of great experiments students can expect to learn during physics class when working with circuits. It's a good way to further a student's understanding.
Energy and Power in Electric Circuits
Of course, you can learn about circuits without understanding energy and power. As wires heat up after electrons flow through them they collide with ions which causes them to vibrate. This vibration increases the temperature which why sometimes wires are hot. More information and practise questions can be found online using trusted websites. Finding supplemental information helps students stay ahead of the game while studying physics.
Household plugs are something everyone sees, but how do they interact with electricity? Each plug in your household connects to the main electricity supply to a commonly used device. In a plugs cables, there are copper wires which act as a conductor. There are many parts to a plug beside the cables. Here are more parts.
- Outer insulation: the three copper wires are safely wrapped with extra plastic insulation to avoid any serious accidents.
- Cable grip: holds the cable tightly into place so that the wires do not become loose.
- Livewire: a copper wire that is coated with brown plastic where the current enters the device.
- Fuse: made of glass or ceramic and contains a thin wire that melts if the current gets too hot. If the fuse is melted the circuit is broken and no more current flows through the device.
- Neutral wire: a copper wire covered with blue plastic that connects the cable in the wall and completes the entire circuit.
- Earth wire: a copper wire coated in plastic that provides a way for the current to flow from the case of the device to the ground if there is a fault. This is a very important aspect because it prevents a person from getting electrocuted the next time they touch the faulty appliance.
Static electricity is the motion of charged particles. For instance, rubbing two things together can cause electrical effects. Static electricity can be a great way to introduce students to electricity. Students can learn about atoms which contain smaller particles such as protons, neutrons and electron. When static electricity happens protons are positively charged and electrons are negatively charged and thus certain objects are charged to affect other objects. Here are examples of using the non-contact forces of static electricity.
Friction is caused when insulating materials are rubbed against each other. For example, when a polythene rod is rubbed with a duster, the friction causes electrons to gain energy. Insulators prevent the electrons from moving forward and therefore the charge becomes static. The properties of attraction and repulsion are used to show if an object is charged. Opposite charges attract and the ones that are the same repel.
All charged objects have an electric field around them with different shapes. An electric field is where charges experience a force and they are usually shown on diagrams with arrows to show in which direction a positive charge will be pushed.The closer the arrows are the stronger the field and the greater the force will be experienced by charges in that certain field.
Electricity can seem like its own large subject, but with some studying and practice, students will be able to understand it in no time. if they are having difficulty you can always hire a tutor. Superprof has 100s of physics tutors in Canada that are ready to help you. They have the experience and knowledge to help you learn the best way. Superprof also offers lessons online and in-person giving you the freedom and flexibility to learn when you want to learn.
Sample Exam Questions and Assessment About the Electricity Topic
There are seven types of questions that can be encountered on an assessment for the topic of Electricity while studying the High School Physics Syllabus. The following are examples of those questions:
- Multiple choice questions: probably the easiest since all you have to do is tick a box. However, be warned that show of the answers may be similar and this is designed to trick you.
- One or two mark questions: they usually start with command words such as describe or explain. These can either be worth one or two marks and you have to describe a scientific topic using short sentences.
- Three or four mark questions: longer answers are required and valid points need to be explained in a logical manner.
- Maths questions: these questions may include graphs and tables and it is essential to show all of your work in order to get full marks.
- Practical questions: when studying GCSE Physics you will need to complete eight practical activities and these assessment questions are based on those. Use all the information provided to write down the correct answer.
- Six mark questions: these are probably the most difficult and need to be answered logically. Planning and carefully reading the questions is essential for success.
- Equations: some of these questions will require you to recall and apply equations you learnt during class time.
Studying electricity can be interesting if students are looking into the world around them. Electricity is everywhere and we need people studying it. Electricity is just one of the topics when talking about physics. Other key topics of the High School Physics Syllabus include particle model of matter, atomic structure, forces, waves, magnetism and electromagnetism and space physics.