So I did a lab in my physics class in which we measured the voltage and current

Question

So I did a lab in my physics class in which we measured the voltage and current of a simple one- light bulb circuit using a multimeter. We then measured the resistance of the light bulb itself. My lab instructions say "Divide your answer for the voltage by your answer for the current. You might expect that the result should be similar to the result obtained in this part, but they are not. The difference is due to a change in the light bulb, not a flaw in the theory. What about the light bulb has changed?" I am having trouble figuring out why this is. The measured resistance was lower than the calculated one.

Explanation / Answer

light offers resistance to the circuit which inn turn depend onn the tempertature as

Rt = R0 (1+ alpha dT)

where R0 is the resistance at zero deg C and Rt is the resistance at it iopertaing tempertuare

usually for this case of filament s this v aries in direct proportion

alpha is the coefficent of electrical conductivity

and dT is the change of temperature

so remember for conductiors temperature also effects the net resistance and net current in the resistant element (here it is bulb)

high temperature   = high resistance = low current

and

low tempertaure = low resistance = high current

so as your result

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