 really about 10 foot candles or so. Task lighting is specific task. Specific task meaning you know either reading or writing or cooking or repairing something you know a task that requires generally about 40 to 50 foot candles or sometimes if you are doing very small working on small objects you may need even a little higher. Accent lighting is the lighting that is used to highlight certain things at home for example a painting or a statue or something if you want to highlight that that is accent lighting and you need you should be able to design lighting for certain areas that's something that you may want to look at. Design in the sense how to pick up you know based on the area let's say you're designing for a general purpose hall wave you have 10 square feet and each square foot requires about 10 lumens which means hundred hundred square feet requires 1000 lumens so that's how you should be able to figure out. Color rendering index you know different lighting produces different abilities to look at the true colors and you need to know the color rendering index it is measured from 0 to a on a scale from 0 to 100 and 100 being perfect colors or absolutely no color shift and that is generally possible in natural light and when you have a room how many lamps are required that depends on how many lumens you need total area and lumens and each bulb gives out a certain number of lumens and how many bulbs you require based on that for example if you have a room of 100 square feet and you need let's say 20 foot candles which means 20 lumens per square foot so every square foot requires 20 lumens so in this case 20 times 100 will be 2000 lumens is what we would be needing for that room and let's say if it if a 60 watt bulb gives you 1000 lumens you need two of these bulbs to get that 2000 lumens so that's how you and not only that there are other factors like reflectance of the walls and also the light fixture efficiency and so on and so forth so you need to know the factors that affect particularly the number of lamps required types of lighting you need to know the differences between incandescence fluorescence and high-intensity discharge lamps you know how you produce the light the process and the basically the hardware that is involved in and you should be able to perform life cycle analysis in other words if you have two different types of lighting for example for example you have incandescent light and you may have CFL and each bulb you know how to perform life cycle analysis life cycle analysis is cost to own and operate for the entire life cycle over the lifetime and remember you have to compare for the same life period both of these not different lifetimes if one bulb lasts thousand hours and the other one lasts 8,000 hours you have to use eight of these thousand watt thousand hour bulbs to compare actually and cost to own cost to supply the energy energy cost and maintenance cost together will be the lifetime cost similarly you have to do for this and figure out which one is cheaper and there is a problem there is an example in the textbook on pages 251 and 252 that talks about life life cycle analysis and I want you to be familiar with this and there will be a couple of problems involving this on the exam and you need to know how to measure efficacy of lighting which is lumens per square lumens per watt watt is the input that is the power that we put in and the lumens is what we get out of a lamp so that we need to know lumens per watt that is the efficiency and these are some of the things that we can do at home like using switches snap switches or using