ntProblemiD 90699465 elationships in a Light Bulb Filament 12 of 12 Part K The f
ID: 1872731 • Letter: N
Question
ntProblemiD 90699465 elationships in a Light Bulb Filament 12 of 12 Part K The filament of the light bulb is made of tungsten. The resistance of the light bulb at room temperature (20 C) measured by an ohm-meter, is about 30 Based on this information, estimate the temperature of the light bulb at 12.0 V. Neglect the thermal expansion of the filament. Express your answer in degrees Celsius using three significant figures View Available Hint(s) Hint 1. Additional numerical information You should be able to look up the necessary reference information about tungsten online or in your physics textbook Hint 2. Relationship between resistance and resistivity Since the length and and the cross-sectional area are assumed to be constant, the resistance changes in the same manner as the resistivity Hint 3. Relationship between resistivity and temperature To solve this, you need to know how the resistivity of tungsten depends on the temperature 942 PMExplanation / Answer
In the problem it is given as 12 V ,but it is 12 ohms
Resistance Variation with temperature is given by
R=Ro[1+alpha*(T2-T1)]
Temperature coefficent of tungsten alpha =0.0045 /oC
=>12=3[1+0.0045(T-20)]
3/0.0045 =T-20
T=686.67 oC
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.