Smith Spring Physics 1B - Tutorial 7 You will be provided with light bulbs, batteries and clip wires.
Hard Rubber As seen in the table, there is a broad range of resistivity values for various materials. Those materials with lower resistivities offer less resistance to the flow of charge; they are better conductors.
The materials shown in the last four rows of the above table have such high resistivity that they would not even be considered to be conductors. Use the Resistivity of a Material widget to look up the resistivity of a given material.
Type the name of the material and click the Submit button to find its resistivity.
Mathematical Nature of Resistance Resistance is a numerical quantity that can be measured and expressed mathematically.
The standard metric unit for resistance is the ohm, represented by the Greek letter omega.
The equation representing the dependency of the resistance R of a cylindrically shaped conductor e. Consistent with the discussion above, this equation shows that the resistance of a wire is directly proportional to the length of the wire and inversely proportional to the cross-sectional area of the wire.
As shown by the equation, knowing the length, cross-sectional area and the material that a wire is made of and thus, its resistivity allows one to determine the resistance of the wire.
Resistors are one of the more common components in electrical circuits. Most resistors have stripes or bands of colors painted on them. The colors reveal information about the resistance value. Use the widget below to determine the resistance value from the colored stripes.
Check Your Understanding 1. Household circuits are often wired with two different widths of wires: Thus, gauge wire has a wider cross section than gauge wire. A Amp circuit used for wall receptacles should be wired using gauge wire and a Amp circuit used for lighting and fan circuits should be wired using gauge wire.
Explain the physics behind such an electrical code. See Answer A gauge wire is wider than gauge wire and thus has less resistance. The lesser resistance of gauge wire means that it can allow charge to flow through it at a greater rate - that is, allow a larger current.
Thus, gauge wire is used in circuits which are protected by Amp fuses and circuit breakers. On the other hand, the thinner gauge wire can support less current owing to its larger resistance; it is used in circuits which are protected by Amp fuses and circuit breakers.
Based on the information stated in the above question, explain the risk involved in using gauge wire in a circuit that will be used to power an ampere power saw. Thus, gauge wire can safely support a circuit that uses an appliance drawing up to 20 Amps of current.
In fact, a Amp circuit is protected by a fuse or circuit breaker that will flip off when the current reaches 20 Amps. If a gauge wire was used on the same circuit, then the breaker would allow up to 20 Amps to flow through it. It could overheat and thus lead to the risk of fire.
A Amp circuit should never be wired using gauge wire. Determine the resistance of a 1-mile length of gauge copper wire.No matter what a bulb is connected to, its resistance is a property of the bulb.
Parallel bulbs must take the same voltage. By the equation for power, the bulb with the lower resistance . You need to assume the resistance of the light bulb is constant.
Then for d.c. Power dissipated = V*I In the case of a light bulb, the current through the load resistance is determined by the supply voltage.
Course Title: Physics. 3. Division: Natural Sciences Division. 4. Department: Physics and Engineering Department. 5. Subject: voltage, resistance, and power in a simple DC circuit - Measuring current and voltage in parallel and series circuits In lab you set up a parallel DC circuit with two different bulbs (X and Y).
You connected. Variation of Light Intensity – Inverse Square Law. Light Dependent Resistance (LDR) Light bulb. Ruler. Power supply. Voltmeter. Ammeter.
Connecting wires and Inline conductors. Physics Essay Writing Service Free Essays More Physics Essays Examples of Our Work Physics Dissertation Examples.
Make the bare bulb light by using the 2-battery pack. Note in your lab book what connection(s) you had to make to get the bulb to light.
Inspect the interior of the bulb socket to see how the appropriate parts of the bulb are connected to the outside metal screws on either side of the socket. Apart from 3 bulbs for series circuit the value of amperes should be less as it doesn’t fit in with the general trend.
Whereas the in the parallel circuits as the number of bulbs increase the current decrease, whilst the voltage remains the same. Analysis: The values of resistance and electrical power have been calculated. (see figure).