phy114 lab5

phy114 lab5 - Physics of a Light Bulb Objective: The...

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Physics of a Light Bulb Objective: The objective of this lab was to investigate the physics of a light bulb involving voltage, current, temperature, and to validate the Stefan-Boltzmann law. Under low temperature, the light bulb obeys Ohm’s law(V=I*R). This means that voltage across the light bulb, V is directly proportional to the current, I. Under ohmic condition, the voltage versus current graph should form a line with a constant slope of R(resistance). However, as the temperature increases, the light bulb will not obey Ohm’s law so that it is by nature non-ohmic at high temperature. This is due the increase of resistance R at high temperature. On the other hand, the Stefan-Boltzmann law, P=A*T^4, shows that the power output increases exponentially by a power of 4 with increasing temperature. Stefan-Boltzmann’s law can be proved graphically in two ways. First, graphing the power, P versus, temperature to the fourth, T^4, should create a straight line with a slope that is close to A, the constant of proportionality. Second, graphing power, P, versus temperature, T, should create a graph that shows exponential growth, and when the graph is approximated to fit the mathematical model Y=A*X^B, the value for B should be close to 4. Procedure:
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This note was uploaded on 04/29/2008 for the course PHY 114 taught by Professor Tsen during the Fall '08 term at ASU.

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phy114 lab5 - Physics of a Light Bulb Objective: The...

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