In the Current Electricity section, you learned about electric charge, current, voltage and other related topics. But, just because you have a voltage does not mean electric current will flow. Electrons also need a complete loop of conductive material to flow, called a closed circuit . Let's look at a light switch. When you turn the switch "on", the switch creates a path that conducts electricity and electrons start to move—meaning electric current flows—and the light turns on. As soon as you turn the switch "off", the path is broken and electrons can no longer flow. The switch is like a drawbridge; switching it on is letting down the bridge so the electrons can cross (just like cars crossing a bridge) and provide energy to the light bulb. Illustration of how electric current can move through a closed loop of conductive material (left figure) but stops flowing whenever the loop is broken (right figure). This figure shows how a light bulb l...
NUMBER SYSTEMS In Hindu Arabic System, we use ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 called digits to represent any number. This is the decimal system where we use the numbers 0 to 9. 0 is called insignificant digit. A group of figures, denoting a number is called a numeral. For a given numeral, we start from extreme right as Unit’s place, Ten’s place, Hundred’s place and so on. We represent the number 309872546 as shown below: 6-units 4-Tens 5-Hundreds 2-Tounsands 7-Ten thousand 8-Lacs 9-Ten lacs(million) 0-Crocres 3-Ten croces We read it as “Thirty crores, ninety- eight lacs, seventy-two thousands five hundred and forty-six.” In this numeral: The place value of 6 is 6 ×1 = 6 The place value of 4 is 4 ×10 = 40 The place value of 5 is 5 ×100 = 500 The place value of 2 is2 ×1000 = 2000 and so on. The face value of a digit in a numbers is the value itself wherever it may be. Thus, the face value of 7 in the above num...
Work: the force used to move something There are 2 basic types of energy: A. Kinetic: the energy gotten from a moving object. A car going down a hill has kinetic energy. B. Potential: energy waiting to be used (stored energy). A ball waiting to be dropped. The heavier an object is or the higher it is gives it more potential energy Force: any push or pull that causes an object to move, stop, or change speed or direction Friction: a resistance to motion because objects are rubbing against each other. Friction causes heat. Bike or car brakes use friction to slow them down. Inertia: when your body is riding in a car and the brakes are slammed on your body keeps moving forward that is inertia. Another example is when you are sitting on a sled and your dad jerks on the rope and you fall back (stay at rest) because of inertia. gravity: an unseen force that pulls two objects ...
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