lass Management Help mework 3 Begin Date: 8/29/2017 12:00:00 AM -- Due Date: 9/1
ID: 1652668 • Letter: L
Question
lass Management Help mework 3 Begin Date: 8/29/2017 12:00:00 AM -- Due Date: 9/11/2017 11:59:00 PM End Date: 9/11/2017 11:59:00 PM (6%) Problem 12: The filament of an incandescent light bulb is made of tungsten which has a thermal coefficient of resistivity of 4.4 x 10- K-1. The filament is initially at room temperature, To = 293 K. When it is connected across a V= 105 volt power supply the filament quickly heats up to T= 3100 K at which time the current flowing through the filament is 0.65 amps. 50% Part (a) Write an equation for the initial current, 10, that flows through the filament when it is initially turned on. (eg wh at room temperature) Grade Su Deductio Potential 0 Submissii Attempts (0% per a detailed 0 END BACKSPACE DELCLEAR Submit Hint I give up! Hints: 2% deduction per hint. Hints remaining: 3 Feedback: 2% deduction per feedback /S 50% Part (b) Find the numerical value of the current in amps when the filament is at room temperature All content © 2017 Expert TA, LLCExplanation / Answer
at T = 3100 K
R = V / I
and R = R0 [1 + alpha deltat ]
V/I = V / I0 [1 + alpha (T - T0)]
I0 = I [ 1 + (alpha (T - T0))]
(b) putting values,
I0 = (0.65) [1 + (4.4 x 10^-3 (3100 - 293))]
I0 = 8.7 A
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