Mid year Review

Exam Breakdown Part 1 Part 2 Bonus 32 Multiple Choice 4 pts each 14 Short answer Technological analysis Bonus

2 hour exam Tech world: 11 questions Changes 4 Magnetism 4 Solenoids 4 Electricity Static 4 Dynamic 3 Circuits 6 Formulas 9

Technological World (11) Motion transformation and transmission systems Speed change based on Torque and gear size Links and Guides Constraints and Properties Multiview drawing Tolerances Increase friction and adhesion of a surface How does an object work

Changes

Changes (4) Combustion Oxidation Visible signs of rapid combustion Fire triangle Oxidation Identify an Oxidation reaction

Types of chemical changes Oxidation: Definition: Chemical change that occurs when a substance reacts with oxygen (O2) Examples Rusting An apple turning brown Particle Model

Types of chemical changes Combustion: Type of oxidation reaction that releases a large amount of energy (light and heat) Examples Fire Fire Triangle

Combustion Triangle Fuel Oxidation Agent Ignition Temperature

Combustion types: Slow Rapid Spontaneous

Static Electricity (4) Elementary particles and their charge How charged particles react while close to one another Bonus Question

Elementary particles Protons Positive Electrons Negative Neutrons Neutral

What does this mean… An element with more electrons than protons will be considered negatively charged A substance with less electrons than protons will be considered positively charged

How do charges react? Opposites attract, Like charges repel

Practice Questions

Practice Questions If I say that by rubbing silk and glass together, the silk gains electrons. Will silk be positively or negatively charged?

Dynamic Electricity (3) Conductive vs. non-conductive Changes in conductivity of a wire

Dynamic electricity

What conducts electricity? Metals Graphite Electrolytes (salts in water)

Conductivity of a wire A wire’s conductivity (how much electricity can pass through in a given time) will Increase if the diameter of the wire increases Increases if the length of the wire decreases Increases if the temperature decreases Change with substance used (copper is the best)

Which of the following plastic

Circuits

Circuits (6) Electrical functions Series vs. parallel circuits Draw a circuit Connection of an ammeter and voltmeter Identify the circuit based on description

Circuitry basics All circuits must have elements that perform the following electrical functions Power supply: Battery Conductors: Wires Transform energy: Resistors, Lights To that you can add Control Switch Protection Fuse

Circuitry Basics Parallel Series More than 1 pathway Independent Lights controlled separately More energy efficient Series Only 1 pathway Dependant: 1 goes out they all do 1 switch controls everything Less energy efficient

Drawing a circuit Read the question carefully Find out whether they are asking for a series or parallel circuit Draw the circuit (1, 2 or 3 boxes) Add the power supply Add and label the necessary components

Adding Ammeter and Voltmeter An Ammeter Measures current intensity Placed directly in the circuit A voltmeter Measures potential difference Measures 2 points

Questions on Circuits A circuit consists of two light bulbs (L1 and L2), a switch, and a power supply. When switch 1 is open L1 stays on and L2 goes out. Close the switch and both lights are on. Draw the circuit

What are the electrical functions found in the following circuit?

Formulas

Formulas (9) Basic Applications Dual Equations V=RI E=Pt P=VI Qualitative V=RI Dual Equations Find the most energy efficient appliance (calculate E)

To solve Read the question carefully Underline the important information and highlight what is being asked of you (what should your final answer be) Find the formula that has your missing variable in it. Identify the remaining relevant information in your question. (If you are missing a second variable you need a second formula) Solve the problem Do not forget to include your units

Calculate the resistance value for each of the following resistors A 2 V 10 A B 5 V 3A C 3 V 20A D 6 V 2A

Question While having breakfast, you notice the following information on the specification plate of the toaster. You also note that this toaster toasts the bread in 1.5 minutes. What quantity of electrical energy is consumed by the toaster's element to toast the bread?

Magnetism (4) Identify the magnetic, non-magnetic and ferro-magnetic substance Magnetic field lines and respective pole Compass over a live wire

Definitions Magnetic: Ferro-magnetic: Non-magnetic Object that can attract objects containing iron, nickel or cobalt Ferro-magnetic: Object that contains iron, cobalt and nickel, that will be attracted by a magnet Non-magnetic Object that is not attracted or repelled by a magnet

Magnetic Field Lines Always go from N to S Out of the North pole Into the South pole

Live wire magnetic fields Right-hand rule Thumbs points to the negative terminal Fingers indicate direction of magnetic field *** If compass placed on wire - Thumb points to the negative terminal - Your pointed index will indicate the North of the compass

Questions

Repel or attract and why? Iron Plastic

Solenoids

Solenoids (4) Magnetic field of a solenoid Factors influencing solenoids Attraction and repulsion of electromagnets

A solenoid is a live wire that has been coiled The magnetic field is controlled by the power supply To find the north Your fingers follow the coil towards the negative terminal Your thumb points North

You can increase the strength of a solenoid by… Increasing the number of coils Increasing the current flowing through the coil Changing the core (what the coil is wrapped around) to something containing iron

Questions