A certain lightbulb has a tungsten filament with a resistance of 20.3 Ω when at 20.0°C and 135 Ω when hot. Assume the resistivit
1 answer:
Answer:
1275.61° C
Explanation:
The resistance of a conductor varies as a function of temperature and it is given as follows
R_0 is the resistance at temperature T_0, R is the resistance at T and α is the coefficient of temperature of resistance
α= 0.0045/°C
R_0 = 20.3Ω T_0 = 20°C and R= 135Ω
T= 1275.61° C
Therefore the temperature of the hot filament = 1275.61° C
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Answer:
4.163 m
Explanation:
Since the length of the bridge is
L = 380 m
And the bridge consists of 2 spans, the initial length of each span is
Due to the increase in temperature, the length of each span increases according to:
where
is the initial length of one span
is the temperature coefficient of thermal expansion
is the increase in temperature
Substituting,
By using Pythagorean's theorem, we can find by how much the height of each span rises due to this thermal expansion (in fact, the new length corresponds to the hypothenuse of a right triangle, in which the base is the original length of the spand, and the rise in heigth is the other side); so we find: